It's not P5 today. And realistically, it wasn't the first time someone laid down that moniker.
It is SEC. B1G. and then Pac12. The first two are going widen the gap, widen the gap, widen the gap. The flow (TV prime showings, slots in March Madness, advertising tie-ins) are going to unequally go to the top conferences and then to their schools. There is now a clear second tier of ACC and B12; as the former Governor/now President of Oklahoma is looking around, there is leakage coming that makes both those two less than rock solid. This will consistently be quicksand. The Dude is going to watch a diminishing position of the West Virginia's type school.
Will it crater with someone making a first move? Might.
By 2025, the tiers will be significantly separate and widening. Some TV/content demand will grab more of the AAC because it is reasonably solid live content at a really lesser cost. That, to me, says that the Fees for the ACC and the B12 diminish.
This P5 is not created for more than a few years of stability.