I just don't see either the SEC or B1G taking too many more schools. The money just can't grow at the rate needed to keep payouts as high as they are now. Every single school that they add, would actually decrease the average of the conference.
I can see with the moving away from linear bundles to streaming that big matchups are going to be a driving factor in re-alignment, not location. (Bad for us). But even still, the numbers don't show that college football is increasing, it's actually slowly decreasing in viewership. They are squeezing blood out of a turnip, and eventually the bubble will burst, and when it does, payouts will plummet, and some companies will go bankrupt.
I predict you will start to see this by 2030 when the B12 comes up again for negotiations. I don't think they will get anywhere close to what they expect, much like the Pac 12, and if we want, we could pick off some of their best schools.