All of this talk about market size and fanbase is almost meaningless. The SEC and B1G are not as valuable as they are because of TV market size. They're valuable because of their draw outside of their markets. Alabama, LSU, etc. are not all that great by themselves. Their success over the last 20+ years has drawn national interest outside of their states and their conference. ESPN values the SEC because people in Iowa, Colorado, Maine, Nebraska, etc tune in. They're a 50 state draw.
What the ACC or any other league trying to keep up needs to do is add teams with the money and commitment to be good enough to compete for playoff spots and make noise in big time OOC matchups. We need to be forward thinking enough to find teams that are like Miami in the early '80's, a team about to hit big on the national scene. SMU may be that. Who else fits that bill?
Your opening is a contradiction. It
IS about fan base size, just not simplistically restricted to one local TV market or even one state. And the interesting part is that there is a huge correlation between a school's average attendance and its ability to draw large numbers of TV viewers. So it is a given that Auburn, located in a small town and the #2 state school and dissqtnt #2 football program in a small state, is always going to outdraw BC for TV viewers, and the size of Boston cannot alter that even a teeny tiny bit.
When you cannot add a PSU, then you look for other factors that can add to the league's football quality and, over time with improved quality, its national TV numbers. First is: state flagship and land grant schools that have some recent football history that matters at least regionally. Such schools will have built-in fans across that state and anywhere its alums live, as well as natives of the state who have made adult lives elsewhere. The AZ schools are a great example, because they do have guaranteed fans across AZ and also in CA, where so many of their alums live.
Another is to add schools that are in local TV markets and states that have proven big numbers watching CFB. DFWc and TX are perfect examples. That state is football obsessed. And while the flagship and land grant are guaranteed those massive TV numbers, any other school in Tim invading the 3 lorivate ones with real CFB history invading over the past 30 years or so, is goin to also start getting much larger TV numbers.
As improving quality of play is so important to a league not filled with large flagships and land grants getting large TV numbers, that league must add schools from TV markets and states that produce a lot of talent.
Those are the factors that the ACC always should have used in expanding. Adding BC was so ed it bordered on criminal stupidity, because it and its TV market and state can be nothing but dead weight for the ACC. They bring nothing that can help elevate a league's TV numbers or its quality of play.
TX is a very large state chock full of top talent and ardent TV watchers of CFB, and only 2 TX schools are in the P2. So that means that the league with the most TX schools that is in the 2nd Tier 2 has an advantage over the other such league.
OH is a large state that is football obsessed almost as much as is TX and that produces a whole lot of talent, with only 1 school in the P2. If ether is only 1 other school in OH that is in the 2nd Tier 2, and that school school is a very large state school, the league that has it has an advantage over the other Tier 2 league.
Right now, the only thing that elevates the ACC a bit over the Big 12 is we have FSU and Clemson, which have more successful histories and proven larger national TV audiences than any current Big 12 schools.