Kamala was just a pawn, placed there purposefully by Biden on his way down.

This was a civil war between the Bidens and the Pelosi/Obama factions. Biden screwed them by deliberately naming Kamala as his chosen candidate (to circumvent a primary) and publicly tied her to the Biden administration’s “success”.

The rival factions couldn’t do anything: if they oppose to Kamala as the nominee, then they’d also be denying the “success” of Bidenomics that would be extremely bad optics for the party and the Democratic presidency as a whole. If they choose to go with a primary, they’d be publicly opposing Biden’s chosen nominee, and that might as well be telling everyone that the party is dysfunctional and nobody is at the helm, just three months away from the election.

The Bidens played their cards right and have the last laugh. Even managed to free Hunter on his way out.