the truth is a tremendous number of powerful people have been extremely careless with that power for a very long time in regards to the threat posed by donald trump specifically and the revanchist right generally. and they are *just now* realizing the problem several years late and panicking
even the rallying around a then-78-and-already-showing-signs-of-decline biden in 2020 was careless! they were as concerned (or more) with keeping bernie or warren out of leadership as they were with removing trump.
The Obama presidency should have been hint enough that the American Right was already off the rails. People were waaay too chill about Greg Abbott deploying the Texas state guard in response to the Jade Helm 15 conspiracy theory
My personal view is that Biden would've beat Trump in '16, and I'm a little surprised I don't see more people criticizing him for not running that year. But I also don't clearly remember why he didn't run that year. We'd be wrapping his 2nd term or a less destructive Rubio term, or whoever.
Periodically certain members of the left freak out, think they lead the fractious coalition because they are so special and important, and after a while realize they do not, and return to the fold