[Genuine Realist]

Take the following hypothetical: ...

I don't think that hypothetical has anything to do with NIL arrangements. 

It does address eligibility requirements for college sports, which touches upon the issue of amateurism. 
However, it really hinges upon competitive balance. Is an older athlete who has already competed professionally in the same sport likely to tip that balance overly far. My own guess is no, and the NCAA should drop that prohibition - but it isn't clear to me and there are clearly issues here.

Most of the posts on NIL assume it's a cover for direct compensation from boosters. A hypothetical that addresses compensation directly seems appropriate.

I don't understand the language about 'competitive balance'. All star players affect competitive balance. One kid could be drafted but accepts a scholarship because his family thinks the G-League is a bad deal (they're right). Another of comparable skill turns pro, figures out it's a bad deal, and enrolls in school. The one plays as a junior, the other tries out for the squad as a freshman. There's no difference.

You don't stop a kid from playing because he's too good. That makes no sense.

[Genuine Realist]

Take the following hypothetical: ...

I don't think that hypothetical has anything to do with NIL arrangements. 

It does address eligibility requirements for college sports, which touches upon the issue of amateurism. 
However, it really hinges upon competitive balance. Is an older athlete who has already competed professionally in the same sport likely to tip that balance overly far. My own guess is no, and the NCAA should drop that prohibition - but it isn't clear to me and there are clearly issues here.

Most of the posts on NIL assume it's a cover for direct compensation from boosters. A hypothetical that addresses compensation directly seems appropriate.

I don't understand the language about 'competitive balance'. All star players affect competitive balance. One kid could be drafted but accepts a scholarship because his family thinks the G-League is a bad deal (they're right). Another of comparable skill turns pro, figures out it's a bad deal, and enrolls in school. The one plays as a junior, the other tries out for the squad as a freshman. There's no difference.

You don't stop a kid from playing because he's too good. That makes no sense.