Perhaps I am too optimistic but I do think some of it will be tamped down when he doesn’t have the huge megaphone he currently does.It's a perfect storm, really. You take the existing large minority of people that feel the way Trump does, add a carnival barker with no shame whatsoever like Trump, add right wing conventional media and social media, and here we are.
I do feel that on the balance, Trump isn't the cause, per se. If he were, once he goes away then it ends. All he did was take what already existed and lit a match. He's a rather large symptom, but ultimately the real problem is why such a large part of the electorate is, in general, highly uneducated and so ready to live an in alternate reality
But I sadly don’t think it will go back to pre-Trump days as once you are down that deep a rabbit hole it is very hard to pull yourself out and there will others, like Carlson, to take up the torch.