The nod is to pragmatism. I’m too old to be an ideologue. Perhaps you have not read by other writings on this, but Biden is a mainstream, police state, extreme capitalist and that is all that he has ever represented. He is also practical and throws crumbs to people he needs to maintain his voting base.
But the national delusion is too engrained to allow any real change until the whole things collapses. This election, as I have said for three years, will not save anything. The planetary disasters, in complex form, will destroy the nation-state system and, worst case, human civilization within fifty years.
Right now the only remaining option is the selected oligarch who is, at least, not a raging psychopath in hock to the Russian mafioso and recognizes that the only thing he can do to have some history at all is to transfer power to a new generation. Harris is also a manipulator and chameleon as that is what it takes to succeed in the corrupt political system that remains.
The stage directions is for Biden to take the stage and perform his final role and slip behind the curtain. The policies that Harris supports are the minimum need for the US as a political unit to survive a little longer until the deluge, literally, washes it all away. But the need for drastic change is well known. We are stranded by a significant minority who have become increasingly insane in the face of the unknown and the lure of the snake oil opportunists.
I think having Biden as a one term transition with Harris actually in charge is preferable to the disintegration into psychopathic delusions with stooges plundering wildly until the shooting starts. Harris is intelligent enough and committed to the right things that she will see reality more quickly than anyone older. Maybe. At least there is some hope. Otherwise we face the final days in rage, turmoil, and denial.