If Trump were ever overthrown they'd happily toss his ass out the White House and within, say, two days be off to the races saying Pence was innocent all along. Not a shred of shame either, probably be quite relieved if anything. Trump's enough of a narcissist that he might not realize (or conveniently forget to himself) how much they don't like him. They'd never say that, but they do say everything short of it. Especially when he rips up their current legislative effort, or shits on it then praises it then dumps it, or criticizes something they just did while demanding they now support something else, or, or, or...
I think they'd find it harder than you're implying. Far too many candidates running have thrown their advertisement dollars in with Trump supporting. While they may or may not privately hate him. A Trump impeachment before the election would be devastating. They may be willing to allow it after November, or possibly after 2020 if he's re-elected. But "tomorrow" is hoping a little too much.
I still think of Cruz: he rode the Trump wave during the primaries, expecting it to end in fire and to sweep up the remainders, but when that didn't work went on the attack ("New York values" and "vote your conscience"). Cruz personally is still a snake in the grass who'll dump Trump when he can, of that I'm sure. And in 2017 I heard a lot of grumbling, and self-consolation, on the Republican side about "President Pence."
I agree with you overall though, and I might even concede your main point: maybe things have changed since then. Certainly, it's become more and more costly to disassociate oneself from Trump, and no one has seen how nasty he might be if he thought he was going down. And there's no doubt in my mind many, if not most, Republicans would rally to Trump to stop any but the most ironclad reason to impeach (the pee tape maybe?). But for now, I think it's likely that Republicans would dump Trump if his Teflon ever stopped working. It'd start quietly, with little life-rafts at first, but a flood would be inevitable.
Speaking of 2020, is there even any hint of who's going to be running on the dem's side? What about the republicans, if they hate him as much as you say, any chance of the completely bonkers idea of a primary challenger from the incumbent's party?
I am curious about the dems though, as much as I don't want to start up the election season any earlier than it has to, the only name I keep hearing is Oprah... despite her continually saying "naw, not gonna." It's scary that's the only name besides a few mentions of Biden and examples of "Young up and comers" who "would be good to run in 7-10 years."
I've heard a number of names. Problem is those names were so utterly numerous and unknown that they went in one ear and out the other. It seems like a desperately crowded field, and the people who waited out Clinton are probably chomping at the bit to have their chance. I wonder how Trump will handle a crowded Democratic field without a single main contender. Will probably spend the whole time thinking about it, and intervening in ways no other President would, like saying he personally likes or dislikes candidate XYZ or that so-and-so is "
totally corrupt" and things like that. It'd be curious to see how the field would handle constant turbulence like that: whether or not Trump's interference would backfire (or succeed from a reverse-psychology standpoint) or if the candidates would all close ranks whenever Trump tries to comment, or what. An interesting dynamic. I bet there's potential for a hell of a book in researching and recording that as it happens. Hmmm...