Democrats can no longer delude themselves they can just sit back and wait for Trumpism to run out. Remember how early it still is
Better yet, the idea that the scandals surrounding Trump will definitely bring down the GOP in 2020. Coolidge won his own term in spite of Harding's scandals, Ford was less than 30k votes in MS and OH away from winning in 76', and Gore won the popular vote and maybe even the election in Florida despite Lewinsky.
The point is, political parties and partisan loyalty (especially in these hyper partisan times) are much more powerful than some would like to think. It's more likely than not that Trump doesn't singlehandley bring down the GOP. There has to be a genuine crisis and a mishandling of it by the Republican Party for them to be cast into the wilderness for awhile.
I doubt even that would do that trick.
I mean the GOP should still be in the wilderness after the Bush years and just two years after 2008, they had control of the house.
Politics are cyclically in this country. As terrible as Trump is and I do believe the GOP will suffer in 2018 and 2020, they will won't be in the wilderness regardless how terrible his presidency is.