I am pretty confident none of the ACC schools are going to de-promote their football to D1-AA or go independent. I think it's a hopeless endeavor to hope for that.
Once the ACC schools we think are going to leave (UNC, UVA, VA Tech, NC State, Miami, Florida State, Georgia Tech, Notre Dame), I am 99% confident the departments leftover would much rather team up with: UC-Berkeley, Utah, Arizona, Arizona State, Oregon State, Washington State, Colorado, Stanford, Oregon and Washington (assuming those three are still around for now) then get rid of football altogether and join private schools with almost no research. Duke will value being in a major conference for academic affiliation/research partnering/tv publicity. The only school that would make half-sense is Wake Forest, but I'm sure they'll follow Duke where ever they go, and they're actually a half-decent program anyway. Boston College/Pitt/Syracuse are proud of their football tradition, they aren't scrapping it.
And if you're Cincy, Kansas, Iowa State, Baylor, wouldn't you rather be in that conference vs. the Big 12? I can see ESPN trying to salvage their ACC network investment by going for this.
Editing to add this tweet, a great follow about college realignment in general. I did not see the tweet before writing but he's spoken about it before: