No offense, but one the biggest mistakes the Democrats are making is believing (or trying to make their followers believe) is that Trump supports are nothing more than a "cult". The change you're seeing in Washington has been coming for some time. Trump just happens to exemplify the "anti-politician" we've been looking for. Is he perfect? No. Is he the most likable of person? Who is? Can he walk on water? Well, there have been rumors... But he is doing, or trying to do what he promised during the campaign.
None taken.
Trump doesn't exist as an isolated individual in the course of history. His nomination and election are part of much larger processes that even his impeachment and/or an election loss wouldn't solve entirely. The Republicans in Congress would be there to stay and would resist a Democratic President as they did under Obama.
So I agree that the fact Democrats haven't taken a step back and recognised this is the culmination of a road we've been on for many years, perhaps decades, is one reason they lack the vision, imagination and leadership to inspire the rank and file members of their own party and the country. Trump is a symptom of something much bigger going on in the Republican Party and in American politics.
Even if you accept Russian interference played
some role in his election in 2016 and even pushed him over the line in a few states, that doesn't explain how 62.9 million people voted for someone who the media and polls dismissed as an un-electable road crash. He still won and the same forces that propelled him to the White House in 2016 could do it again in 2020, whatever your assessment of the man or his administration.