Trump has historically underperformed in poles and because of the electoral college advantage that Republicans have, Biden probably needs to be at least up four or five points on him, which is what he was last election and it came down to 20,000 votes across several battle ground states.
yes, Trump lied during the debate. Trump is the worst candidate in the history of the United States and him being elected president would be a catastrophe for democracy. Which is exactly why many people in the Democratic Party including - if reports are to be believed - apparently Barack Obama, are trying to have Biden pushed out right now. That Biden is now taking a cavalier attitude that “he’s going to give it his best shot, and if he loses, well he tried his hardest and that’s what counts”…when his own campaign has been framing this threat from Trump as being detrimental to democracy, is the height of hubris.
There are numerous reports that they’ve been shielding him and his mental capacity for a long time now trying to drag him across the finish line. The cat is out of the bag, and it’s a pretty big gamble to assume more things are not going to happen between now and the election. Is that a bigger gamble than switching candidates? I don’t know but I think it is.
No one alive is probably fit to do the job, it’s an impossible task. Those who may come close, would probably never actually want it. And of those who remain who do want it ( which already might make them not worthy for the position) are probably not electable due to the forces of capitalism preventing such a candidate from getting elected.
So what is left is simply a pragmatic choice of the lesser evil. Many people are acutely aware of this and have gotten over it. I suggest until you manage to enact some sort of drastic systemic change you get it over it as well.