"If everyone hates her, how did she win state offices?"
A) CA has a weird primary system that often results in people polling low numbers make it to general elections
B) Have you SEEN the absolute freaks the GOP puts up for office here?
The problem with bypassing her is the optics it presents to black Dem core and Dem-leaning voters.
Replacing Biden would mean getting the components of his existing coalition all on board, post haste, and that would have an extreme opposite effect.