Before the P5, the Big 8 and SWC were both major conferences until they merged and half the SWC lost their seats at the table. There were six power conferences until the Big East got picked apart and essentially demoted. Before that, independence was viable for more than Notre Dame but Penn State, Florida State, Miami, West Virginia, and Pittsburgh were all good teams who went to what were essentially power conferences from 1988-1991 or so.

We've had 3.5 major shakeups with major conferences pulling in more elite teams while other conferences suffered or folded in the last 30 years, pretty much one per decade but with the Big East's demise being a bit more gradual. I don't see a reason we won't have another in the next decade.