Kamala is not well-liked, has no charisma, and polls even lower than Biden. I'm not even counting the polls post Biden stepping down because that is akin to a dead cat bounce. That is a term used in the stock market to describe a decling stock that has a temporary increase before continuing its inevitable decline. The real movers and shakers of the Dem party know she has no more chance of beating Trump than Biden did. The fact that Obama hasn't endorsed Kamala is telling. For all intents and purposes, he is the current kingmaker of the Dem party, and no one is getting the nominee without his approval. If she is going to be replaced, I would expect it to happen at the DNC convention.
I remember people saying the same thing about Biden, and yet, here we are. These are unprecedented times.