I highly doubt the Big 12 and ACC turn that down if it's actually on the table this time.
And really, they shouldn't. The SEC and Big 10 breaking away would ruin everything officially and formally, period. And they seem willing to do that (even though I think it would make them less money) because a large part of realignment is being driven by these administrations' desire to be both exclusive and injurious to the schools they look down on. Greg Sankey and (maybe to a lesser extent) Tony Petiti want to inflict harm on the schools outside of their leagues, just because they can.
So if they offer you something meaningful, I say you take it. Because if you push back, they'll find some way to blow this all up and ruin it for everyone.
Unfortunately, the red button of college football is in the hands of insatiable blood thirsty maniacs.