Vote for the change you want to see.
The Republican party got remade because trumpists showed up and outvoted the party elites. No reason it can’t happen for the Left except for laziness and apathy.
If all the progressives furious about the state of affairs now had shown up for Sanders in 2016, I doubt we’d be in this hellish timeline. Sadly, he needed the young progressive vote to show up.
That cultural win gets won from the bottom up, the people need to vote politicians like AOC and Bernie into every seat that comes up for election in every layer of government and push every neoliberal incumbent out. From local school board elections to the senate. That means that people need to show up and vote in every primary and election and not wait for the big one once every four years. The left wing of the party needs to put more focus and money in these smaller elections and put actual leftists or progressives candidates on those local ballots. That’s how the Tea Party and Maga republicans gained power inside the GOP.
I bet many of the Bernie voters have never voted in a local election in the years prior to that primary.