The Democrats aren't that stupid. They are fully aware of Harris's unpopularity. She might be the only candidate that would lose to Donald Trump. They're not going to take that chance.
The only way she gets to be president is if Biden dies and then she'll only be a placeholder until the next Democrat primaries, which she won't win.
I’m not sure who the GOP would have on the ballot. I’m talking about if Biden wins re-election and she remains
the VP. Then Biden steps down and she becomes President.