abandoning wide swathes of people
Because forgiving college debt and giving you $50k towards your first house and bringing prescription drug prices down is abandoning you? Fixing our rail system is abandoning you? Repeatedly saying they're going to tax billionaires is abandoning progressives?
It's not like we give them enough to have the power to actually get big things done. When we do give them a little, they have to bring in the vice president to break ties in the Senate.
In this regard, it's not like Republicans wield power any better. They couldn't even repeal the ACA. It's just that they get more credit. First, they get credit for every Dem initiative they stop (even if it's not real). The reverse isn't true. Second, everything the Republicans do get done tends to be negative and stings more than the positives.
I know you want to abandon billionaire money. You want Dems saying the right things to you, in a closet where nobody hears them. Because if you don't have money, you lose elections. Period. That's a big problem that needs to be solved, but it can't be solved by people who lose elections.
The Dems absolutely could have tried to appeal to the progressives more instead of moderates. Clearly, in hindsight, it'd be worth trying something different. But I doubt it would have worked. People weren't happy, and they were going to take it out on the incumbent party. And right now they'd be hearing "why didn't they appeal to moderates?"
My point is that it's more complicated than just "appeal to progressives instead of moderates". The Dems have more realities to deal with than we give them credit for.