Since this is ultimately a cute parlor game and not a forum for discourse on our coming economic crackup, here's how I (somewhat satirically, since most of this makes way too much sense for the honchos running major college athletics) envision things playing out within the framework of my greater societal predictions, assuming we're not all farming weeds and chucking spears at each other within the next decade. While somewhat cognizant of the various grant-of-rights provisions at play, I couldn't be bothered to parse them too closely, so take this as a rough approximation:
https://docs.google.com/spreadsheets/d/119M688Ga4B7yoafGLqmHwx1hmbf9bpK6hxL7IgGHMwk/edit?usp=sharing
Brief synopsis:
ACC: Finally realizes that aside from Clemson it completely sucks at football (Virginia Tech is only a football powerhouse if you're a Virginia Tech fan) and reverts to the basketball-centric and Mid-Atlantic-concentrated conference of academic heavyweights that it was always meant to be. I waffled between putting Clemson and South Carolina in here, but ultimately concluded the package deal made more sense in a still robust cash-cow, football-focused SEC, along with Florida State and Miami which are actually football brands that people care about.
Big 12: An unhappy but acceptable marriage of most of the old Big 8 and the Texas portion of the old Southwest that's not actually called "The University of Texas", which has been flirting with independence for nigh-two decades and ultimately decides that that is the better course. Arkansas, which is in the Ozarks and makes no sense in the deep-south SEC, flip flops along with neighboring Missouri and once again gets to play its old rivals Baylor and Houston every year, which while somewhat dissatisfying to Hogs fans, is no less interesting the its annual bouts with LSU, where the outcome was really never in question.
Big East: Another instance of getting the band back together, the northeastern ACC schools who jumped ship in the mid-to-late-aughts and the Catholic 5 schools finally realize that they are better off together than they ever were apart, in the sense that everybody but their respective fanbases find them completely uninteresting when they're not playing each other. Cincinnati, Louisville, and Temple are allowed to join the party on the relative cachet of their athletic programs and geographic proximity.
Big Ten: Actually ten teams, finally, with apologies to Northwestern, who is finally kicked out of the conference (and major college athletics generally) for being the dead-weight money-suck on the conference coffers that it is and more or less always has been.
Independents: The University of Texas finally jumps in with both feet and joins Notre Dame (Catholics) and BYU (Mormons) as the third-largest denominational football program in the country (Texas Football)--assuming Texas doesn't just become its own country by this point.
Pac 12: The only conference that doesn't change, as it is the only conference that currently makes relative geographic sense. Alternatively, Tesla might not have devised fully-electric charter buses that can get you from Boulder to Seattle by this point, so it might be more of a traditional Pac 8 thing, with the Arizona schools, Colorado, and Utah joining some kind of weird Mountain West type thing. Who knows--nobody watches any of those teams anyway.
Southeastern: It only makes sense that a bunch of Sun Belters who have no concern about anthropogenic climate change (if you believe such a thing even exists) and spending ungodly amounts of money on college athletics maintains an absurdly unwieldy conference map stretching from College Station, Texas to South Florida to Lexington, Kentucky. The SEC wins the next 100 college football playoffs and like half of the next 100 NCAA tournaments. Vanderbilt gets the Northwestern treatment because nobody gives a shit about Vanderbilt sports--including people who go to Vanderbilt.
Memphis and UCF: Whatever. **** 'em.
***BONUS*** "The Great Midwest": All of those college basketball-only schools from the Midwest that people other than college basketball diehards don't even remember exist between the second week of April and the third week of March the following year band together to form a college basketball-only conference that they hope people will remember the other 49 weeks of the year. They ultimately fail in this regard, but the college basketball diehards get a kick out of it.