Several days ago, even Josh Marshall was ruminating about the possibility of Trump bailing. In one sense, whether Josh does it or we do it, it could be considered just idle speculation of something that will soon reveal itself. But in another sense, it has real value because it allows us to voice presumptions and predictions which act as a check on our grasp of the dynamics involved here. If our predictions end up being way off, then we'd better rethink our conceptions.
The closer we get to the convention and election, the more inexorably Trump is roped in to his present (apparent) trajectory. So if he's going to bail, the sooner the better for him and his reputation/brand - and his ego. If he manages his way through to the election, then he faces what looks like a very probable and historic level massacre delivered by an old lady (or maybe two old ladies) to him and the GOP. That cannot seem like a positive outcome to him.
The smart people I attend to pretty much concur that the GOP will not likely stage a convention coup because of the internecine battles that will certainly erupt with all the electoral consequences that will follow (for some unknown duration). On the other hand, if Trump continues to collapse in polling (because of his brain/mouth) the estimations of relative damage might change and some new candidate replacement look a better bet.
Or, if they can
encourage Trump (in the Mafia sense of that term) to bail, then that would cast a more agreeable light on a replacement. This may be what we're seeing now in the broad (if apparently incoherent and cowardly) GOP condemnation of Trump. "It's not a coup, he did this himself" would be the line. And if that replacement was an acceptable figure to some significant portion of the base, that may well be seen as the way out.
With all that in mind, consider Paul Ryan's present behavior.
Quote: "I am going to keep being who I am, I am going to keep speaking out on things where I think it's needed, where our principles need to be defended, and I am going to keep doing that, I hope it's not necessary," Ryan said. "But the last thing I want to see is a another Democrat in the White House"
He's principled, you see. And selfless. And above all, loyal to the party. Meanwhile, offending no one (or at least as few as possible).
Then consider that Ryan's first gig out of graduation was working for the predecessor to the Koch brother's Freedom Works. Would their huge operation get behind this guy? In an instant. Is such a contingency already set to go? I have no doubt at all.