Well, in order to win, you need a majority. To get a majority, you need to have the candidates. To have the candidates, you need to vote.
People do not vote and then complain that the things that require voting in order to take place aren't happening.
No. Democrats don't run good campaigns and have terrible choices in candidates because they don't have a unified, vision of what America should be like, expressed in good public policy and therefore they lose.
They go around pandering to minority groups and single issue voters to collect votes.
If the Democrats acted like a political party with a concise ideology instead of a cartel funnelling money around to losers, maybe they wouldn't act shocked when they lose.
Being the "sane and normal" party isn't enough. Pandering to gender and race like a humanities grad student isn't enough. Free shit and tax breaks isn't enough.
It never has been enough. The only difference is the country and the entire world is in crisis and the middle classes are moving to the right to secure their place in society at the expense of everyone else.
Neo-liberal technocratic parties can't stop it.