Without a long back-and-forth...
The only thing that changed is that what had been cheating and now allowed is now ok, so, UK, Auburn, etc. that already were doing such things under the table or behind the scenes are now not only able to do it publicly, but, they can do it on a grander scale because there is no regulation any longer.
This whole notion that kids suffered in any way is simply not true...not even remotely true for that matter...as is the idea that they are getting "what's due." The idea behind NIL was that the schools should not be able to profit off of a kid's direct NIL, or, that the kids should be able to do so...no school is profiting by a student-athlete doing a commercial or helping at an event for a charity, but, kids are now getting paid for it.
If kids don't value their full-ride scholarship, let them forfeit it and pay for it with the money that they can make through NIL...as, absent the scholarship (and platform that it provides), their value is, ironically, pretty much nil.
Purdue's issues are largely indeed Purdue-issues, but, just because schools that cheated previously are ahead of the game, or, schools that could not compete because they did not cheat can now buy their way back to competing does not mean that it is right, much less even some sort of "good" thing...it is the reality of the moment for sure, but, it is indeed a scam and a facade.
It is not complicated though as you suggest...not at all for that matter...it is merely a case largely of what had been cheating no longer being such, and, schools (and, apparently even states to your point with respect to Missouri and Tennessee) just figuring out how to exploit that to the greatest degree.