you improve the world with sustained iterative action
you vote in the primaries. get left candidates. show up in the general. get democrats, left or not, to at least hold the line. rinse, repeat
what happens? things slowly move left
the person who doesn't vote, and waits for magic perfect leftist candidate to spring forth from the democratic establishment, of all places, and expects perfection right now or they can't be bothered is just a lazy entitled idiot