Outside looking in it sounds like a lot of internal pressure to drop out AND a fear of trump. Even if he loses the election he probably will have enough juice to ruin Desantis‘ next Governor run. Haley might hold out because she is effectively retired. Plus there is a pretty decent chance Trump might get convicted.
His conviction has a very high chance. And the courts taking their time would actually work against him. Because any ads will hammer his court troubles home relentlessly. More independents abandon voting for him as he seems even less viable. If he wins some of the legal trouble follows him into office(notice how very few people are really discussing that fact? It's an ace in the hole!)
The Biden impeachment falling short is the first domino, however. That's coming end of February. A large but not total piece of Trump voters will become disillusioned after that. They really really want an impeachment(think the If Not Before flags) and they also know everything Trump has going against him
About 10% of their base will fall back come election time when the impeachment fails. They won't do it publicly of course. I see you laughing but it's coming. Screw your laughs I have inside connects.
More states will get him off the ballot as well. Colorado opened the gates for that. He will get knocked off of one important swing state that hasn't tried it yet. Haley's team knows all this is coming so she'll hang tough. Problem is she is a female and a minority. Hard sell for the gop voters. They'd rather take the L. A black male got 2 terms so the white guy after him oughta get 2 terms. Only fair in their eyes.
Biden is being handed a second term and everybody knows it. The ecomony on the upswing will be icing on the cake.