The DUmmies have already heavily lessened the Dems' chances in the next several elections:
As their threads after last year's elections proved, they didn't learn a thing from their loss. They didn't realize that a major factor contributing to their loss was that Hillary's language and their parroting it exposed them, and the Democrats as a whole, as the mean, smug, condescending elitist pricks that they are who look down their noses and spit on (Not to mention sling baseless accusations of racism, sexism, homophobia, etc. at) anyone with differing views from them on any subject. Most average American citizens don't want to vote for someone who they know views them as brainless, racist hillbillies, so the election went to Trump. Afterwards, the DUmmies' response has been "No, it's not that we need to humble ourselves and reach out to those with differing views; It's that we really ARE so much better than all those brainless, inbred, Bible- thumping racist rednecks in Flyover country and they're just jealous of us, and we should double down on that and on making sure everyone knows we know we're so much better than them! That'll help us win in the future!"
Though, of course, I'll bet everything will happen the way you predict, that'll further slide things in our direction.