They never change because people only vote centrist dem or further right.

Except no they don't, every time the dems run to the center, they get beat the fuck out. The only reason rightwing and centrist dems do well in primaries is because the billionaires and the party elite will do anything to keep it that way. There's a reason Bloomberg dropped out the moment Bernie was no longer a threat.

Left policy is overwhelmingly popular with the people because it helps the people instead of the capitalists. It becomes even more popular when it's implemented, hence why even rightwing parties in countries with universal healthcare never run on switching to the american system.

The dems didn't lose due to protest votes, they lost because they ran to the right and nobody came out to vote because rightwing policies are unpopular. Which is what I have been saying would happen since 2020 if Biden doesn't fight for us. Shit, when I was phonebanking for Biden in 2020, when I got young potential voters who were already activated, I didn't have the heart to tell them that none of the issues they associated with the dems, emptying the cages full of migrants, regular checks for people who couldn't work during covid, free healthcare, free college, weren't part of Biden's platform.