If we have say 8 Blue Bloods, obviously they could all participate in four years twice in theory.
If we have say 16 programs with realistic chances to make a playoff, it gets dicier obviously, but all 16 COULD do it in four years of course, in theory.
The problem of course is one can pencil in Clemson Bama Ohio State in most years and the other 11 are vying for slot 4 often as not.
As we have noted, ten years ago Clemson/Bama were not dominant, and they may not be in five more years. Ohio State seems position to make the playoffs more than ha;f the time, it would appear.