Here's a quote form a PennState fan from the comments here,
"Full Disclosure, Penn State fan here and much respect for Utah. You have to move now. The problem is the money. In a few years there will be maybe50 viable teams in CFP football. If you don’t have the money to play in that league, no amount of fan support or coaching will bridge the gap. The PAC 12 (10-9-8) is not getting the deal done and they are not going to get the money necessary to keep teams in play. With no where else to go, then you better get in the Big 12 now. At least their Presidents and Commissioner understand the new landscape AND care about football. The majority of PAC 12 Universities and the Commissioner are not being realistic about what is facing them."
So it appears that in one future scenario, some B1G (and probably SEC as well) fans think it will cull down to about a top 50 team P1 conference. I suppose that is a possibility. They would have to break from whatever their existing conferences are, all at once though, basically, to do this. Yes?
I am not as well versed on realignment as many of you here, but more realistically I see (in the limited future that I can perceive) a P2 (B1G, SEC) and one P3 (Big 12?), then whatever is leftover from that, as the 'leftovers'. This scenario involves the ACC being ultimately absorbed by the top 3 conferences.
In this scenario, I would no longer be interested in college football unless these top 3 conferences totaled at least 70 teams, ISU being one of them.