The impeachment stuff is of a piece with something I suspect the high-echelon of the democratic party is well aware: Without Trump as a foil, they really don’t have anything like strong, broad support.
So, I expect them to keep that particular fire burning as long as they can. And I expect Trump will do his part to play along. I wouldn’t be surprised if the next few years are marked by yuge Trump rallies all across the country.
Which will make for some interesting theater.