The nice thing for the broadcast networks is that sports still fit their broadcast model. Since people want to watch sports live-action, and the broadcast model is based on advertising revenue scaled by how many eyeballs are watching that particular event, sports are one of the few entertainment options that still fit the eyeball model well.
How many of you know (and are sick of) the Dr. Pepper Fansville commercials? Most of us have seen those over and over. On the flipside, I have no idea what commercials run in my family's favorite scripted broadcast shows. We always FF right through them.
So the broadcast model is going to stick around for a while. The cable subscriber model-- or what I also refer to as the forced subsidy model-- on the other hand, is already dying off. Cable networks are already dropping the BTN in some of the B1G footprint. And cord cutters are skipping out on cable/DirectTV/Dish in ever-increasing numbers. The value in that model is diminishing rapidly. So the revenue from conference networks that rely on that model-- specifically the BTN and SECN--can only follow suit and diminish accordingly.
I see the college football revenue model sliding back to where we were 10-15 years ago with Tier1 and Tier2 contracts dominating. Since the Tier1 and Tier2 broadcast models won't have room for every single football game that's currently being broadcast via the cable subscriber (forced subsidy) model, as Gigem points out, there will be a lot of other streaming options available to the conferences, and/or individual schools, depending on how the contracts are written up.
Those revenue models aren't going to drive realignment. Something else might, like a split from the NCAA due to pay-for-play or other macro issues. But in that case, I believe the idea of conferences as we currently know them will change dramatically. I think it's likely some football-only and/or basketball-only alliances are formed, while the non-revenue sports remain regional, or BECOME more regional than they currently are in cases where schools are playing WAY out of their regions (WVU, Rutgers, etc.).
Just my thoughts. Could be wrong of course.