I agree, but the likelihood is less, so you really have to choose between the lesser of two evils. Moderate Republicans will never vote for Trump because when he gets to the big stage one-on-one with the Democratic candidate (Hilary), he is going to implode, and badly.If they push him out and he runs 3rd party Hillary would also win in one of the biggest landslide victories in US history, too.
The only way to win is if he implodes by himself, really.
At the very least the GOP having their own gives them a shot to say to the RNC base that we're just like him without the crazy, so come on over to the good side.
It's slim, but it's better than nothing.