I'm not trying to argue, I would love everything I say to be wrong
I posted the legal definition, of which would stand up in any court in the land, regardless of any sort of clearinghouse, CBA, salary cap, etc. FMV can be capped on things like commodities, eminent domain, etc because there is a very clear ability to compare one asset to another based on locality, prior sales, historical trends, supply/demand, etc - but not on what an individual can make for "services rendered" or not in an endorsement or sponsorship deal.
You can't compare athlete A to B or trends because they all have different attributes and their value is dictated by the school's need, the sponsor's desires, the player, the locale, National visibility, the player's demands, team success, etc. The only way you could try to determine some sort of FMV would be to look at something like recruiting ranking or something crazily arbitrary like that. That would be absolutely bonkers.
But that still doesn't hold up. Arch Manning at Texas is going to be worth a hell of a lot more than a higher ranked in-state QB that goes to Iowa State.
Let's use this as an example. The median salary for a Fortune 500 CEO is $17mil/year. But it ranges from the highest - TPG Inc at $199mil/year to the lowest - Warren Buffet at $413K/year. Most have some sort of additional, non-salary compensation that can be worth vast ranges. Nothing but shareholders can control those salaries or the compensation packages, because company performance alone isn't a one-to-one evaluation.
The Clearinghouse that is being pushed through is specifically regarding pay to play,
not pay to sponsor/endorse.
Again, the Clearinghouse will be effective in concept for limiting what schools and collectives can pay athletes, that's a great move in itself. Nothing however will be able to limit the endorsement deals, it's outside of the control of the Clearinghouse. IF the Clearinghouse tried to limit it, it would fail quickly at the first sight of a lawsuit.