Meh, politics tends to cycle, one reason is "progressives" are led by arrogant elites, who use social issues to divert from economic issues, just like conservatives, LGBT instead of inequality. The Clintons were too tied into Wall Street. Pandering to minorities instead of focusing on class issues exposed the corruption in the Democratic party.
Problem with Bernie, Warren et al is they're much like Trump, ignorant of economics so they'll propose thoughtless populist solutions that they have no clue how to pay for. And people aren't stupid, they know they'll pay higher taxes for these policies - they want to know they'll get the benefits, not some "other." Which is why the Roosevelt administration designed social security as a "pension," not welfare for the elderly (which is what it is, a highly progressive policy that results in most working class people receive far more than they pay in).
These things tend to work out, Trump is destroying the Republican party by forcing it into a corner where it's core support is over 40 white males - a base that will literally die out. The cultural wars have already been won, the far right can fight some rear guard actions but demographics dooms their agenda.
What the Democrats should do but won't, because their base is just as moralistic and intolerant in their own way as the Christian right, is to seize the moderate center - because that would result in a realignment that would dominate American politics for decades. That means tone down the hot button issues, realize immigration is not a key issue (they don't vote), focus on economics, the safety net and use measured language, don't talk about "rights" (if it ain't in the Constitution it ain't a "right", it's a desired policy) and don't patronize white working and middle class people.
Sure, a lot of Trump's support are deplorables, but a lot is also middle class Americans who wanted to register a protest against the smug liberal elite (who are just as corrupt in their own way - the classic profile of the CEO, a hard working kid from the mid-west who worked his way up has been replaced by the child of privilege who goes to elite schools and builds the right connections) who impose pain on the middle class while shielding their own children from competition. Busting glass ceilings so women with rich husbands can also get richer doesn't appeal to the woman in Iowa working a crappy job to help pay the mortgage - that's the kind of feminism that doesn't resonate in middle America.
The Democrats need to move away from moralizing to focusing on how people with differing belief systems can live and work together - you can't ask conservative Christians to accept homosexuality as "normal," you can ask them for tolerance and good manners, "render unto Caesar . . ." By being the party of reasoned discourse they can box the Republicans into a corner, but if they remain the party of elite moralizers they provide Trump with the perfect strawman.
We'll know if the Democrats are ready if they give up the "resistance," stop the talk of impeachment, and nominate someone who's not from New York, California or Massachusetts in 2020 - that is, someone like Obama or Bill Clinton who has had to campaign in Trump country and can talk to more than just the coastal liberal elites. A candidate from the coastal echo chambers will struggle to beat Trump. For the Democrats to win, they have to present a coherent vision of the American they'd like to build, and not merely distaste for the current POTUS.