The Democrats never seem to do much about the system when in power.
If they'd done something they would've lost more. Voters, who on average are near retirement age, hate it when you do anything because they think it'll affect their retirement.
In this case they were blocked by Manchin/Sinema from anything like filibuster reform, but they did get some big important economic reforms in.
You nailed my biggest complaint.
My new unhealthy conspiracy theory is democrats like being perpetually in the minority where they can talk a good game but don’t actually have to follow through on anything. That’s why they always tack right and try to compromise with people who call them enemies and groomers and demons. “We’ll welcome them into our cabinet” never sat well with me in the era of Trump.
Polls show voters think Harris/Walz were too liberal, not the other way round. They mostly haven't gone right either; Biden campaigned as a moderate and ran as the most progressive administration in my life.
(Which was good! But voters hated it because they don't like change and don't like inflation.)