Agree. I've seen dementia. This isn't dementia. Whatever it is though is enough to convince a lot of fence sitters to not vote for him. I have zero concern about those who reliably vote D. I am extremely concerned about those who are open to voting D and might not this time.
A non-representative sample--but reading a number of focus group things--suggests that most of the actual fence sitters in swing states will probably vote for him anyhow. (The one guy on the BBC coverage who said otherwise was a libertarian from Florida, which: pfffft.)
And there is very little more frustrating than hearing that having a cold and a stutter tangle Biden up for a moment is enough to convince people Donald Trump isn't worth fighting against.