I would guess lately it has more to do with the Big East's inability to keep it conference stable, starting with the VT, BC, and Miami defections, and now Pitt, WV, and Cuse. They haven't really had a "big name" football program in a while, and when programs do step up (Miami, VT, WV), they leave the conference.
Thats just my opinion from the outside looking in. The ACC has been weak in football for a number of years, at least at the top. Probably since FSU had those great teams in the 90's. But they have been stable as a conference (mainly at the expense of the Big East).