From another site:

[CecilOne]

Originally Posted by AtlUmpSteve

They (the NFHS rules committee) believe that there are significant numbers of schools, areas, and even complete states, where the pitching level is already so bad that they cannot mandate two feet on the pitching plate, let alone 43', without making the "have-nots" even worse competitively compared to the "haves". They believe that toughening the pitching rule in either of these two categories runs the risk of schools without competitive pitching disbanding their teams if no one can or will pitch for them. In face or that possibility, it would be inappropriate to adopt a rule making the game more competitive for the more advanced participants, if the result is reduced participation.

The obvious counter argument is that bad pitching will remain bad pitching, so why not make the game more competitive offensively, and force feed the creation of the higher level of play. After all, does NFHS baseball pitch from 55' feet to compensate for lesser pitching? Do they shoot basketball free throws from 14' to compensate? As long as ASA remains at 40', NFHS can remain at 40', being a national standard for those of high school age. If ASA moved to 43', there would be increased pressure on NFHS to change (although they have steadfastly ignored and refuted the pressure to force two feet on the pitching plate).

While I agree that this helps others understand the NFHS viewpoint, there is a signficant difference between the example rules. A pitcher who wants to have both feet on the PP can do so, as the rule allows either option. The distance woud be fixed, so a pitcher who wants 40' would have no choice.
I'm not saying this means it should be changed or not, just that the comparison is not exact.