Lots of growing rumours going round that Biden had a TIA (a 'mini' stroke) last week in Las Vegas, rather than COVID (or alongside COVID), which would fit with a lot of the activity going on right now despite announcements he is over his COVID (not being seen at all apart from a single voice call yesterday, powers being redelegated behind the scenes, his sudden drop out and a sudden focused support for Harris, nobody there to meet Netanyahu, etc). Whilst TIAs in themselves often do not have permanent consequences, at his age and presumed stress levels the chances of a full on stroke in the time after are likely concerningly high.
Now it could be a lot of people putting two and two together and coming up with 5, but definitely something to watch as chatter levels about this are going beyond mere internet rumors that are easily quashed. If these are true and there is a long term risk to his health, then we might be seeing signs of a transition of power prior to the election.
But hopefully we will see him in the next couple of days which will silence this.
I must admit, I had a similar thought myself this morning. It feels like his presidency has already ended, not just his re-election campaign.
Basically, the Democrats, despite knowing that something is obviously wrong with Biden and that he shouldn't be running for another four years, have been trying to do a 'Weekend at Bernies' with him for as long as possible. I think the plan was always to switch out the nominee at some point, but they have suddenly run out of road and had their hand forced. My only surprise is that I didn't think the nominee would be Kamala Harris, given the absence of public profile she's been given throughout the Biden presidency.
I do agree with some of the Democrat anger though, that they have been made to go through 'fake' primaries, only for the candidate to be imposed on them. However, even people voting for Biden in the primaries must have been deluding themselves a little.
I know it may not be anything like this, but enough of the situation is sufficiently odd (most notably the not having actually seen him) that you can see why the rumour mill sparks up. A friend's Dad had Vascular Dementia and he went from 'a bit vague at times' to needing sectioning, literally overnight. Whatever it is, though, its a real shame as with a bit more honesty, and self-awareness, he could have gone out on his own terms, enjoyed a good and well-deserved retirement rather than going out this way (though that is the way for all politicians, it seems. If I were Vladimir Putin, I'd be touring the Med on my Yacht by now or if I were Donald Trump, I'd be down the golf course every day). The two-term limit is, pretty much, the only good thing about the US political system.