They may lose their P status but I don’t think either will completely go out of business like the SWC did.
For all practical purposes, if they lose their 'power' status, they will being competing for last place. They simply won't draw the eyeballs they did with the land thieves and sexat, and eyeballs = dollars.
They'll fall further and further behind until they and what's left of the PAC12 probably form some 'super-conference' of whatever is left over in one last attempt for relevance before the almighty dollar speaks and only the B1G and the SEC remain as real contenders annually.
As long as the framework of a conference exists with an autobid for the basketball tournament they will have members. CUSA dropped down to five members last year but managed to rebound. The Big 12 has managed to right its ship after the loss of TX/OK.
As football dollars continue to increase at dramatic rates, it won't be long until more conference move like the B12 has, adding schools in one sport or the other, but not necessarily in both. Just watch the B12 viewership numbers drop in 2024 or 2025 - they will be less and less attractive for ad dollars going forward, because no one honestly gives a crap about the four G5 teams they added.
A conference with a better name like the ACC will always be around.
I predict the ACC will be dead before the B12 or the Pac12. Clemson and FSU obviously want out, and if the conference decides to distribute revenue unevenly, as some are asking, it will rot it from within, and quickly.
ACC has two good programs, they will be poached in a few years and it will finally be widely considered what it's been for the last two decades - a G5 conference with a couple of good teams.
The B1G and SEC have destroyed the other conferences. They may look alive right now, but in 10 years their conference revenue will be closer to the MWC than to the SEC or B1G.