I completely disagree. While the debate felt disastrous, there is ample evidence that a not insignificant amount of swing voters either saw past the old man voice to what he was actually saying and standing for, as well as recognized how badly Trump did, even though literally everyone only focuses on Biden, just like always.
The worst possible thing we can do right now is just jump ship this close to an election. Biden has one bad debate, and is fine the day after(another thing people conveniently love to ignore) and we're just supposed to restart. What if the new candidate does poorly at the second debate? We just pick another person again?
Biden beat Trump last time. Trump has only grown weaker and lost support, while Biden has been extremely successful. Everyone is upset about the debate performance, but it will not be even close to as impactful as people are convincing themselves it will be.