Democrats feel safe to continue their course because most of the US "left" refused to work on building an alternative and abandoning them in 2024. Third parties got even less percentage of the vote than before.

Abandoning the Democrats is the only option. Look at Zohran and AOC caving to power at every opportunity. Mamdani had to drop support for challenger to Hakeem Jeffries because we can't have people actually challenging power! (Democracy btw)

Even Pelosi used to be known as a "progressive" when she started.