What if the GOP replaces Trump? There are a lot of ways he could become unelectable in the next year. So how would Biden do against a fresh Republican candidate? (My guess is Biden could lose if he doesn't have the "anyone but Trump" vote, so I hope the Dems have a fresh candidate of their own ready to take up the torch soon.)
GOP is locked in. Their base won't accept anyone else.
I think the GOP has rolled out it's freshest candidates and they are running now.
They won't bring in a new candidate, if Trump can't run he will cut a deal with Desantis and back him under an arrangement that Desantis pardons Trumps charges. Desantis is not a platform that will help the American people.