His personality and method may be politically idiosyncratic, but he tapped into a very real voter base and, more importantly, managed to engage a pretty slippery donor base - a petite bourgeoisie that:

a)doesn't rely on immigrant labor and can afford to be hawkish on that front

b)doesn't send its kids to public schools and can afford to tear down that institution

c)isn't beholden to traditional American foreign policy interests for the success of their business (or doesn't believe themselves to be)

d)isn't served by the traditional GOP pandering to the interests of giant corporations (or, again, doesn't believe themselves to be)

People keep noting that the argument on the right at the moment is miming the usual argument on the left: the radical flank of the movement is threatening a stable American political synthesis and will cost the mainstream candidates, and therefore the party, a solid foothold. But that observation is true in the particulars as well, that the political movement that Trump wrangled is one that can't necessarily be counted on to show up for conventional GOP candidates. If the GOP wants him gone, they can't just excise him abruptly without alienating a lot of support that they really need. And the additional problem is that those guys are already rich, so they're not as easy to scare with the threat of electoral loss. I mean, they're already scared all the time - of women, of people who aren't white, of gay people, of their kids hating them, etc. but those fears have mostly solidified into a political identity. They don't expect Trump to fix those problems, they only expect him to legitimize their fear.

That's not really saying anything though. Reaction never goes away; it just mutates. The lifelong Democrats right now that are starting to get nervous about their property values or starting crying and gnashing their teeth because their kids had to stay home from school during COVID are going to be ripe targets for Republicans who want to turn down the volume on the craziness, and a not small amount of suburban ones will flip the moment their material comfort risks being sacrificed to help somebody else not be miserable.