If a team is booted out of the CFP for losing a conference championship game, you'll see teams begin to decline to participate in the, or conferences will eventually begin refusing to hold them at all. Their ranking might drop, but they will remain in the field barring exigent circumstances.
In fact, teams have always dropped at least one spot after losing a conference championship game — until Alabama this year. They likely remained at #9 due to their regular-season win over the eventual SEC champion, and the clear desire to finally rank Notre Dame and Miami directly next to each other, allowing for Miami (and the ACC) to get in due to their Week 1 win over Notre Dame. Conversely, BYU dropped a spot after losing the Big 12 CCG, but it was already out of the field, so it doesn't really matter.
Leaving Notre Dame ranked over Miami as long as they did was silly; the hissy fit that Notre Dame is throwing now is ridiculous. They should have been preparing themselves for this outcome from the moment that Duke won the ACC championship.
Tangent, I think most of us here in Norman were pretty surprised by the Bama rematch; seems the prevailing thought was that Bama would drop to #10 and we'd get either Notre Dame or Miami. In any case, looking forward to being there in person next Friday night. Boomer!