It may not happen due to all of the personalities involved but there really is no good reason for them to be different. They are really only different because neither side wants to compromise with the other over difference that don't matter.

At every single level, they could be made the same aside from the timing differences (different length game, shot clock, etc.), ball size, rim height, and maybe some court dimensions. None of those elements are playing rules. All of the playing rules should be 100% the same from pros to kids.

And there are other sports where it is done. It can be done without much difficulty in just about every sport IF the involved parties wanted to converge. But that would mean that someone would have to give up a position of power.

So you want the travel rules to be the exact same? You want contact in the post to be the same? You want the Technical applications to be the same? What about a 24 second shot clock? Better yet, you think the players could handle those rules differences?

And that does not include the many abilities of officials that cannot get basic rules right at the high school level, now you want to add complicated NCAA or NBA type applications as well? We have a hard enough time to get some basic contact being called a foul and now we want to add changes or better yet make those rules apply to HS kids to grown azz men? The NBA would be less fun to watch for the average public and NCAA and NF players would have a hard time adjusting when many players have a problem dribbling, let alone getting across the division line in 8 seconds.

Peace

Absolutely! No reason to be different. At least that way you would be less likely to have people bastardizing the rule and calling it in a way that doesn't match any of the levels or calling it at one level as it is specified for a different level.
As far as the rule goes, YES. No reason to be different.
Again, Yes. No reason to be different.
Now, if you actually read my post, I suggested that there would be timing differences for different levels....that means the shot clock could be longer for lower levels.....even 8 minutes if you want. But the rules of when it starts and when it resets should be 100% the same.
That is the question you should ask about the current situation. I'm suggesting that there be no rules differences. If there are no differences, what is there for them to handle.
Oh please. There really isn't anything more complicated about the NBA RULES than in NCAA or HS that needs to be different.
Advantage/Disadvantage or whatever the current terminology would be is all you need to differentiate the levels. Let the pros play through more contact while kids are called more tightly. The rules can be the same, just the threshold of what becomes a foul vs incidental can change.

And again, before you refute my post with points relating to 24 seconds or 8 seconds, you might want to actually read and understand my post. If you had, you would have never made those points.

Could you make the rules all the same? Sure you could, but there are rules needed in the pro game, that don't exactly vibe with the ideas and philosophies of NFHS and vice versa.

Player gets fouled (non-flagrant) during a try and can't attempt his free throws...well are we going to go with the NBA rule and allow the opposing coach to pick the shooter along with not allowing the player to return for the rest of the game? Or do we go the NFHS route and allow the coach to pick the replacement shooter along with allowing the player to return in the game?

The NBA rule is needed because winning is of the uttermost importance and their rule discourages, say...Dwight Howard from getting "hurt" and allowing the coach to put a better shooter on the line...and bring back Dwight soon after (and now we'd get into substitution differences between NBA/NFHS but we'll keep this simple). In NFHS, where winning isn't the most important aspect of the game, their rule works fairly well for that level (though I think they should go the NCAA-M route).

There are also rules that are made the way they are in NFHS because the talent disparity between officials is vast. So in essence, there are rules and enforcements that are kept simple for the entire officiating pool. You want to burden some officials at the high school level with having to determine a secondary defender versus a primary defender, and then adjudicate an RA play...when some can hardly get a regular block/charge play correct? And then possiblly add in whether a play originates in the lower defensive box (NBA and NCAA-W)?

Heads Block, Tails Charge ...
 

Hey. I get it right 50% of the time.

That is the ultimate point. And if the NCAAM changes the block charge, we have officials at the high school level that already have a problem calling the block charge with just the players going airborne.

Pros do things because they know how to get an advantage. That is why there is a rule about throwing something on the court and counting a basket (OKC Fisher play) and no such rule would be appropriate at the high school level IMO.

Peace

Why not? All of those things, if they just took the NBA rule, would work just fine in a HS game, even with average HS officials. For that matter, a lot of HS officials already try to call a HS game with a lot of those rules even though they are not correct for HS.

Sure, if you got some NBA or D-League officials, and told them to call a high school game under NBA rules, then sure, you could have a game since a lot of the rules in essence are the same. And maybe that's your point...you could have a game, but I would say that some of the consequences of using pro rules in a high school environment would not be appreciated by those involved in that level. For instance, NFHS wants some real meat behind a coach getting a T...so what do they do? Award two shots and possession to the other team, AND the coach loses his box. Don't think they want to go with one shot and the ball inbounded at the point of interruption. Hell, it might even be worth it for some coaches if that's all the penalty is. Could you still play a game using those rules? Sure...but I don't think those at NFHS would think the penalty is appropriate considering sportsmanship is of greater importance to them.

And when a lot of average high school officials can't get a simpler rule set correct with the NFHS, then no, I don't think they'd do just fine.

I'm sure they could come to a common ground or the NFHS could just apply post game sanctions for T's if they wanted....much like the NBA applies fines for certain actions on top of the game penalty.

You could still have a few optional rules such as the coaching box/seat belt rule. Those are no big deal. I'm mostly talking about the actual game rules and game situations. No need for BI/GT to be different. No need for the 10 count or shot clock starting point to be different. No need for the pivot foot or travel rule to be different. Etc...
Part of the problem is that there IS more than one ruleset, not that any one is too complicated. Since many officials typically watch a lot of NCAA M or W and/or NBA, it isn't that they can't get one set right, they often mix and confuse 3-4 different sets. If there was only one set of rules, they would have a much easier time with whatever the rule set is, even if it had some more complicated elements.

I don't think the rule differences are really the problem. The problem is officials who just don't bother to learn the rules they are working, and the coach/fan misunderstandings are the same. Too many fans and coaches (and some officials) have misconceptions that aren't true in any level of ball.

Examples:
1. Defender must be "set" to draw a charge.
2. Players must go behind the half-court line for intentional foul or technical foul free throws.
3. It's a violation to go out of bounds (due to momentum) and be the first to touch the ball upon returning in bounds.

The rule differences aren't that big of a deal. With different people in charge, and each of them having different priorities, some of the differences even make sense.

Would it be better if everyone magically agreed to a universal rule set? Sure, maybe a little. But not significantly, IMO.

I see officials mix up rule sets more far more often that I see them make the kinds of errors above. This occurs with otherwise good officials that work more under more than one rule set, with rookies who don't yet know that the levels are different, and then officials that don't care to try to know the differences. The issues above that you listed are largely (but not entirely) issues of non-officials. But for those officials with those problems, no amount of rule convergence or divergence will change help their problems. They're just poor officials.

Most of us have to know this is not going to happen. You are not going to get the NCAA Committees to agree based on gender, then why would anyone seriously expect the NBA that has an agenda to make money and make their game watchable comparable to an organization that sole purpose is to deal with education at the core of their mission.

Peace

The primary reason for the NFHS to be different is that they fund their operations through the sales of their rules books. All of the educational goals could be met just the same if they just adopted in total the entire NCAA or NBA rule set. But, they'd lose their revenue stream.

That brings up the question of whether the NFHS in its current form is even justified if they can only operate through a forced artificial revenue stream. Is all of what they're doing serving a valid and necessary purpose or is it just a big boondoggle.

As an example, take soccer...same rules for kids of all ages from kindergarten all the way to the pros but the NCAA and NFHS inject theirs in the middle when it is a HS or NCAA game. If the same rules work for 8 year old Johnny and Suzy as works for Pele or Messi in soccer, basketball could easily do the same. In fact, FIBA is making efforts to be more in line with the US rule sets rather than striving to be different.

Not sure what soccer you've been watching. Every league my kid was in, from 4 to 12, the rules changed every single year.