I think the obvious question is whether Joe bows out SOON, and who replaces him (KH odds on bet). Rampant speculation out there of course, which in itself is very damaging to his prospects. Any candidate will have missteps over the months, Biden can't have ANY. Even a minor gaffe, trip, weirdness caught on camera, will get blown up on him after the debate. I think he's starting to hear a LOT of Democratic voices whispering, or flat telling him, to rethink this. He HAS to say he isn't dropping out of course, any lack of certainty from him on that point would end it.
If he somehow doesn't drop out preconvention, I suspect there will be a very damaging move to replace him at that point, something Democrats could hardly afford. So, my GUESS is before end of this month, he will try and appear to be a statesman etc. He'll remain in office and let Harris run.
If Trump would simply SHUT HIS MOUTH he'd win I think. I don't think he can do that.