Why did Hillary lose in 2016?
Democrats turned off by Sanders getting shafted in the convention.
Hillary too far to the left for moderates of both parties.
Draconian gun control.

What is the Democratic party doing for 2020?
Getting set to shaft Sanders in the convention again.
Going even farther to the left than in 2016.
Even more draconian gun control. (Hell yes, I'll take your AR15!!)

Failure is expensive. When it happens it's important that you get your money's worth out of it by sitting down and objectively looking at what went wrong so you don't do it again.

This seems to be far, far beyond the capabilities of the Democratic party.