Seriously, it just makes no sense right now.
You merge, you open up the ACC GOR and suddenly that merger is PAC+ACC minus everyone the big 10 and SEC takes. That remaining ACC is worse than the big 12, plus adds a lot more travel distance.
The only way it could happen imo is if the teams like FSU find a way to blow up the GOR, those teams leave, and PAC teams like Arizona are leaving for the big 12 at the same time. Then maybe the PAC-6/8 might find it appealing to merge with the ACC leftovers vs inviting a bunch of MWC teams. The problem is the likelihood of these things happening simultaneously is slim. More likely is the PAC suffers losses, has to backfill, and by the time the ACC is in a position to merge the PAC has all these other teams.