Come on. This is not a good post.
Learn how to win a damn election by not taking your base for granted is probably a good start. With the exceptions of Trump and Sanders, the establishment candidates conflated Super PAC and contribution cash with effective basebuilding and on-the-ground strategy (aka GOTV). The lesson is that, if you want someone to vote for you, then you have to listen to their issues and find a way of convincing them that your platform is inclusive enough to incorporate these issues.
You can be a carpetbagging snake oil salesman, like Trump has proven to be, or you can take the route of legit progressives like Sanders, who for all the crap that folks like ChrisL gave him, is pretty much the poster child for how to get people involved in the process. The DNC primary strategy of front loading states that Clinton had no chance of winning in the general turned out to be a poor predictor of her actual support and, in taking her base for granted, she poured resources into Texas and Georgia instead of making sure there was no chance in hell that she would lose Wisconsin, Michigan and Pennsylvania.
Those are a few lessons that establishment Dems can learn and, by making sure that Ellison leads the DNC, I think the party could really make some strides forward for 2018/20.
But instead, Dems and establishment Pubs are in denial, blaming rubes and third party voters, rather than engaging in any sort of reflexive exercise to consider why their candidates all lost so badly in spite of so-called common sense.
Board liberals and board republicans that didn't vote for Trump should probably be doing this instead of this half-assed snark/trollfest that's come out of this election.