I don't see it. She's always been unpopular, and now she's not a "winner" either. I would be able to imagine it if she won the popular vote, or if the election was in general very close, but I think Democratic voters will simply find better options. And therefore I don't even think Harris will embarrass herself by trying — I think she'll start a foundation or be a private attorney or speaker or consultant or something like that.

(to be clear, I give ~5% odds that Biden steps down early for symbolic reasons, and ~5% that I'm wrong + time discounting)

Interesting that her odds are basically the same as those of winning the election later this year. Implies that if she loses the majority does not expect that she will continue to have a political career.