What do you mean we won't forget? Mitch cruised to reelection just a couple months ago. Dems lost seats in the House as well. Had you seen all the people voting for Biden sticking with the Dems down the ballot then I think Republicans would have been pushing just as hard as Dems to get this vote done and get him impeached and convicted, but people didn't vote against Reps, they voted against Trump.
Reps believe, and are probably right, that if they can successfully jettison him now, they won't suffer many repercussions by the time the next election rolls by. If they play it just right, all these crazy Trumpkins will just go back to not voting and the slightly less crazy will decide that they can't support communism or abortion so of course they are going to go back and vote Rep top to bottom.
This is my concern. It will take a lot of hard work to make sure this doesn't happen, and if we don't start the work of tying Trump to the Republican party at large right now, we've already lost. So far, Dems are doing a terrible job of making that argument. Let's hope they get better quickly.