He was closer in 2020. But in 2020, Democratic primary voters got a very simple choice: double down on moderate neoliberalism, or try progressivism. Democratic primary voters made a very, very clear choice, and Biden wiped the floor with Sanders from the day it became a two-man race. Biden won nearly two-to-one in vote share and in delegates and won numerous states that were Sanders' base of support in 2016.
Is there a progressive wing in the Democratic Party? Yes. Is it a lot bigger than it was ten years ago? Yes. Is the fact that we've been right all along becoming more obvious by the day? Yes. But are progressives the majority of the party? No. Are we competitive in national primaries right now? No. We have simply not convinced half of the half of the country that votes Democratic that we are in the right.
Part of that is our serious problem with the black vote - it's very hard to win a Democratic primary without it - but it goes well beyond that. Republicans have very successfully painted us as a bunch of frothing-at-the-mouth fools who want to waste all your money sending men to leer at your daughters in locker rooms, and we need strategies to convince people otherwise. We need to play politics. What that looks like, we can debate, but we have so far failed to win the game of rhetoric even though we are, objectively, right.