If the NIL world has taught us anything, it's that extra money is almost always additive and not a replacement. My guess is any extra NIL cash from a 2025 Vegas tournament will be on top of the already-in-place arrangements. Maybe WeWill will be able to re-allocate some cash from basketball, but I bet not much.
I would imagine it'd all be part of the total compensation when they discuss these things after each season. Any school is going to sell the total package they can get there, whether it comes from a collective, a tournament like this, or other outside NIL deals.
But yes, given the market keeps moving upwards, being in a tournament like this is less of a 'this funds half the basketball team' and more 'this helps keep us from falling further behind'
I imagine this is going to be the way almost all the MTEs go to some extent. At least any that want to have any prestige. Probably bowl games as well.