The democratic electorate is still pretty right wing itself, the fact lots of them preferred Iraq war Bush cheerleader Bloomberg over Bernie speaks volumes for me.
A lot of the democratic electorate is very naive also assuming that if once Trump goes that's it we're saved, we're back to 'normal'.
And then Republicans will start winning surprise special elections, the dems take another shellacking in the 2022 mid terms, GOP gain the house, senate and governorships, retaining the likes of Ron DeSantis and Brian Kemp, that's what normalcy was under Obama. And then the GOP White House back in 2024.
Don't get me wrong I think Biden's potentially a good short term candidate for beating Trump, but predictably its going to all end in tears once again.