I don't know what is going to happen to the college postseason. I don't disagree with anything you say, but I'll add that if/when the playoff is expanded to 12 teams we are going to see more and more players from even playoff teams start sitting out.I am hoping that with playoff expansion, most of the bowls go away. They are just going to become opt-out fests anyway. Even players who have limited NFL prospects will opt-out just to make themselves seem more important than they really are. And we will see opt-outs even for playoff teams.
With a 12 team playoff, most bowls will just be seen as a consolation prize that no one cares about. Keep some of the larger/more historic ones around that aren't apart of the playoff like the Citrus Bowl, Alamo Bowl, Las Vegas Bowl, Outback Bowl, Sun Bowl, Gator Bowl, and leave it at that. The Dollar General Bowl or ObscureNicheOnlineRetailerSponsor.Com Bowl can go the way of the dodo bird.
A huge part of the problem I think is the 3-4 weeks of time between the final game of the season and the bowls/playoffs. Guys would just rather prep for the NFL than go through another 3 weeks of practice, not to mention they have all that time to get swayed by their handlers. Maybe that big lapse in time gets fixed with the expanded playoff and that "problem" goes away. I don't know, but no reason the CFP Championship needs to be played on January 9th when there are only 4 teams involved, by the time the game comes around most people have already seemed to have moved on from college football anyway.