We won't know how many have jumped off the bandwagon until the trial, but I doubt many will die in a bunker for anyone, not even a huge donor, let alone a loser like Trump - who only joined the party in 2016, and led it to a wipe-out in 2020. Some of the new blood might, but they're really of no account. Primary threats work both ways ...
That's the kind of thing their donors want from the Republican Party, and let's not forget the influence they wield. They want a party which can win and deliver, and a Trump-whipped party really can't, to my mind.