I don't think she's running to win. The Democrats have already accepted that they're not going to win the presidency.
When Biden was the candidate, there were concerns he'd be so unsuccessful that most Democrats downballot would be wiped out. That's why they replaced him.
Harris was brought in to maintain the status quo to protect the Democrats downballot. But they're not trying to win the presidency.
To win the presidency, Democrats would have to depart from the status quo, and the Democrat machine has no intention of doing that, and Harris is not bold enough to do that.