The biggest problem with the ACC is that it hitched its wagon to smaller schools and to "second schools."
Big Ten and SEC have eight "state U's", 2 or 3 "second schools" and only one small private school each. The ACC has only three "state U's", 5 "second schools", and four small private schools.
The biggest advantage you can have in college athletics is to be the "State University". That means that nearly everyone in the state who isn't otherwise affiliated is automatically your fan and booster. Even South Carolina, who is historically moribund and currently mediocre, has a bigger fan base than Clemson.
Note that the only two "second schools" on the list are Auburn and Texas A&M, which are by far the richest, biggest, and most historically successful ones. The only "second school" with equal or better historical success over a long history is Georgia Tech, and we just don't have the fan base, size, or recent success that A&M and Auburn do.
This is the biggest reason why we should have taken West Virginia rather than Boston College.