Great article. In addition to the points you make about Sanders vs. Trump and your calling it a year ago, my Lyft driver, a 60-ish white American-born male, called it for Trump two weeks before the election. If anybody had been paying attention to the fact that white people speak with forked tongue (OKCupid proved it in a different context a while back https://medium.com/@ranjeettate/inter-racial-internet-dating-behavior-predicted-a-november-surprise-trumps-victory-3a9d0610fd56#.1ilaco576) they would not have paid any attention to the polls and analysis, this would not have been a surprise at all.
Sadly, not just the Democratic leadership, but their middle-of-the-road sheep are also incapable of introspection or learning anything. 4 or 8 years from now, if there are elections again, the Dumbocrats will have another BlueDog even more conservative Democratic candidate who we will be asked to vote for since there will be an even more crazy Republican candidate and “this is not the time for …”, and they will again be shocked and dismayed and will start their hand-wringing.
I wish the Democratic Party would go away.