If Duke and WF "dropped down" from full time P-5 football would the ACC toss them out? Why would the ACC do that? Nothing is gained. Suppose that only Miami, Clemson, FSU, UNC, NC State, VT, Syracuse, and Louisville competed full time at the top level. There is no reason to toss out GT, UVa, WF, Duke, Pitt, or BC. In fact the upper division can play and the lower division can play.

NC State would play 7 conference games - Miami, Clemson, FSU, UNC, VT, Syracuse, and Louisville. We would continue to play Wake Forest and attempt to schedule bi-annual games with GT, Uva, and Duke.

My point is that two tiers need not mean conference expulsions

WF, Duke, UVa, BC, Pitt, and GT could invite SEC straggler Vandy and play a 6 game conference slate. Duke will continue to play UNC, Wake will put UNC on the schedule, VT will still play UVa. This Junior Varisity ACC football would have 6 league games, and school like Vandy would still be able to play TN, Alabama, etc., etc.