teams come in, that just means the smaller conferences are splitting their small payments in more ways.

In fact, the status quo kind of favors the P5 having them in. The fans of the lower conferences still pay attention to FBS playoffs because that is their division. An MWC team might never get into that playoff, but they still would pay attention to FBS playoff as the playoff to which they would belong if they could ever qualify

If you completely separate those teams, that's bad news for the P5 because fewer of those fans will care to watch the P5.