You are assuming that leftward momentum is what the democrats want. I am sure a couple do, but the establishment democrats showed their hands when the super delegates prevented actual progress, and shut down referendums that won to establish ranked voting on state’s levels. Without motivation to change they will not because they got theirs.
And no i don’t want fucking trump being president, using his presidency to quash his lawsuits, damn Ukraine, damn Palestine, sell off what little progress our civilization made to fighting climate change, remove further rights from the vulnerable groups, establishing Christianity as the national religion, kill off all our agent for money, establish the president breaking the law as a with qualified immunity, rewriting the history books, burn and silence dissenting thought, further pollute the judicial system with cronies, and pardon neo nazi criminals.
It just sucks knowing that no matter what i do the US is directly responsible for yet another genocide, and in 4 years it will be de santis or who knows trump running yet again, and it will again be “now is not the time to rock the boat, vote blue no matter who, or else “”democracy”” will end…again” now and forever more as justification to block actual change and then force conservative democrats to win the primaries.