The thing you're forgetting though is that Kamala is ALSO a shitty candidate like Hillary and Biden was.
As others have already pointed out, she is the only candidate who polled worse than Biden against Trump. She's nowhere near the level of charm and charisma Obama was.
At least half the country thinks she's a Cultural Marxist that will destroy America (I wish). And her fanbase is nearly identical to Hillary's was (suburbanite wine moms).
Of course her being younger, not part of any political dynasty, and also actually non-White could tip the scales in her favour. But we'll see.
What do you expect from the same country that thinks means "evil antisemitic hate symbol!!"
It's like Germany learned nothing from the last century and is still trying its hardest to be on the wrong side of history.