The whole "Name Image Likeness" thing is a ruse, at best. These kids aren't being paid for their name, image, or likeness; they're being paid to play. So my wish is that this bs is set aside and call it what it really is - pay-to-play.
Tyrese Hunter isn't going to UNC (or wherever) because his name will pay him $1M/yr. He's going to get paid that because the donors think he can add to W's. His name, image, or likeness will not add any money to a business because of advertising. It's just stupid.
If ISU is smart they will begin having the "kids" sign NIL contracts that tie them to the area; a non-compete so to speak. I had to sign one with my company and they should have to do the same.
Non-competes are super hard to enforce, and in several states they are specifically banned by state law.
The first time a kid tries to break one, is the mega-billions university going to sue some low-income or no-income 19 year old for breach of contract? Optics are "not good" for that, to say the least. Maybe you could sue the poaching university for "tortious interference" or whatever that is.
I get what you are saying, and I think there is a potential solution/mitigation along those lines. Maybe you have a clawback clause on your NIL if they leave, or an agreement that any future NIL you sign with someone else has to have 50% go to the previous NIL funder, something like that. Kinda like a buyout clause on a coaches contract. You're gonna take my coach? Well, you gotta pay for him to break his contract. It doesn't end buying players, but it makes it more costly and will reduce it somewhat.
What this all is right now is unlimited free agency with no salary caps. That is not sustainable. And the 0th law of economics is that if something is unsustainable, then eventually it will stop.