The problem is simply that the ACC does not have enough marquee matchups. Duke-Carolina is great... in basketball. What is the biggest marque matchup in the ACC? FSU-Miami? Clemson-FSU? Would certainly have to be one of those two. In the B1G sure they have their lackluster games. No one cares about Rutgers vs Indiana or Purdue vs Northwestern. But they have multiple schools with huge alumni bases that fill 80,000+ seat stadiums and will watch all of their games. They have bigger alumni bases than even most SEC schools although I would argue the SEC has far more sidewalk alumni than any B1G school with the possible exception of OSU.
ACC? How many schools have 80,000+ seat stadiums? FSU and Clemson, any others? No attendance doesn't' drive revenue like it used to but the fact those schools can support the need for large stadiums speaks to fans interest. Pitt has a huge stadium only because they share with the Steelers. Miami also shares an NFL stadium but fans don't show up until they are 6-0 or better. Reality is, football is driving revenue and the interest in ACC football is nonexistent. I could sit and watch LSU-Florida even though I have no interest in either team. I'm not going to watch NC State play Syracuse and I think most here probably agree.
I don't know what the solution is but I think it will come to a head soon when SEC money starts coming in. FSU and Miami aren't going to sit by while Florida brings in 20mil+ more in media revenue. They could try and sue ACC for breach of contract for not providing as competitive of a platform and then bolt for the SEC. Would that give Tech an out to go to the B1G? Does that conference want GT football?