At the FAR OUTSIDE. More deals will be for a few thousand dollars.
I think we all tend to assume that people who are famous or well-known or who model can suddenly command these massive salaries that we can only dream of. Not true.
Again, take billboards. Sure, Devonta can probably be a valuable billboard ad guy in Tuscaloosa. But outside of Alabama, what is the value of some random 20 year old kid who wears a helmet, and is thus unrecognizable to most people who don't obsessively follow Alabama football? And the value of paying Devonta to be on billboards all over Tuscaloosa...is far less than $100K.
Now, online ads could conceivably bring in a bit more. There is no geographic limitation. But, again, think about all the times that YOU have been influenced in your purchasing decision by some spokesperson in an online ad. I'm guessing that's "not a lot". Again, nothing worth paying a college junior "six figures" to do.
That's all. Maybe when you add up ALL of the opportunities, a kid could earn six figures. But that would have to be one helluva hustle, and don't forget he has to go to practices and classes too. And don't forget about accounting for your income and filing your tax returns.
I think there will be some natural limitations on how much any student-athlete can earn. That's why those of us who can see how easily an "unlimited" system could be perverted do not want to allow situations where a student-athlete can "miraculously" earn millions by passively allowing a ton of people to "generously" pay for his NIL rights.