The officials in the ND-Northeastern game used the packs and the officials for the Butler-Texas game had them at the beginning of the game. I wonder if they switched at halftime.

And now they're back on for the Villanova game... which included a delay in the first two minutes to correct an inadvertently stopped clock!

Maybe they only have the four packs and don't have time for the officials to switch them between games??

Sure it could!
You put an array of IR sensors around the rim (each like a garage door opener's electric eye)
The programming on the back end of the sensor looks for the decreasing/increasing pattern that resembles a round object going through it. The several sensors would be able to accommodate a ball that is passing through at an angle, or off-center. The clock only stops when the ball has completely passed through, and enough time to account for its rate of descent, which could also be accounted for, by using the rate at which the sensors track the rise/fall of the ball.
Using Fresnel lenses around the inside of the rim, the time could be determined down to the millisecond! And with acoustic sensors and pressure sensors around the 3-point line, coupled with tracking devices within the ball itself, we could even determine if any given shot is a 2- or 3-point shot without the officials even having to signal! Goal-tending/basket interference calls would be a thing of the past! We could know when the ball is released if it has a chance of going in, and not penalize a team if the ball is going to miss!
Just wait to see what will happen to the game after a bunch of bored engineers put their heads together to make it better! :D

TL;DR: We have the technology. :p