The funny thing is, that despite Biden's atrocious performance, there have already been reports that undecided voters are allegedly supporting Biden after the debate.
That, plus his speech on the next day also got a lot of acclaim. I think we are well past the point where a bad performance in a debate could decide the fate of an election. It used to be that a weird way to yell "yeah" could sink your campaign, but not in 2024 anymore.
Dropping Biden now would be political suicide. He has his bad days, but he also has days where he's really effective. I don't like some of his stances, but I still think he's the best bet to beat Trump in November.