You seem to be assuming the Dems don't think Biden will win. The whole reason he won the primaries was the assumption that he CAN win, and I think it's a good assumption. He's leading in Florida, and Trump can't win without Florida. He's leading in Pennsylvania (where he was born) and in Michigan, and if he wins those two, even without Florida, he wins, as long as he holds Minnesota, where he's leading by 10 points. He's almost certain to win the actual vote count, because he'll win the Blue states by huge margins, while, if Trump wins, it'll be purely on the basis of the Electoral College, and he'll win the critical states there by small margins. So, even if he wins, which I think is unlikely but possible, Trump will again be an illegitimate President, the choice of a minority of Americans.
Were you asleep during the primary, because that is not what happened.
The Dems were looking for someone, anyone, that could beat Trump, and pretty early on the Dems realized that was not Biden, which is why he did so bad at the start.
Unfortunately for the Dems, he still did good enough to not drop out, but he was still doing pretty piss poor. The whole democratic vision in the beginning was that Bloomberg was going to come and save the day, but he totally flopped at the debates. This then lead Bernie to shoot up and every one have an "oh shit" moment. Remember Chris Matthews (who I actually respect even though he believes in the opposite of what I feel and should not have been forced out) warning the party about this? This then caused the party to look around at who was left and somewhat electable, and in a panic, they went with Biden, overlooking their best shot, Klobuchar.
If Klobuchar had won, I would seriously be reconsidering my vote right now along with plenty of other Trump supporters I know.
This is why Biden got it, plan and simple. He was the result of a panic choice, from all of the stablished Dems to quickly endorse whom ever they could, to keep Bernie from getting it. You are fooling yourself if you think otherwise.
But now the party has a huge problem on its hand, Biden's further cognitive deterioration. He is getting worse and worse as the days go on. He is getting all of the rest he needs, but he still cant be on the cuff in his pod cast. He cant read off of a prewritten teleprompter either. They even tried to mix both in and he cant do it. His "fire side" chats have been a total fail, which you can see by just reading the faces of the people his is interviewing going into total despair.
The last podcast his campaigned released this weekend was of his wife talking for him and why he would be a good president while Biden stood there, not saying a word, just smiling and nodding.
That is not the look of a president. If I was a party leader, I would be looking for some way to replace Biden.
Insofar as the polling, Hillary had a lead twice what Biden's are now in all of the swing states at this point in the 2016 election. I also feel a sizable amount of those being polled lie due to the belief that they will be negatively recorded in some list somewhere or to just screw with pollsters (which has been documented to be the case amongst conservatives).
You guys have a big problem on your hands, and you brought onto yourself. Even my mother, a huge anti-Trump Dem, just does not think Biden is capable of being president given his cognitive decline.
You should have picked Klobuchar! She was the only candidate without baggage who was nearest the center. Not to mention she is the closest version of Trump the Dems have, a total bull dog politician. She did not knee cap Buttigieg at the last debate; she ripped off his legs and beat him to death with them. This is why I feel she is the best VP choice, because she cant really take it to Trump.
FYI, another thing to consider, Dems like young candidates. Dems have always went with a younger person when it was younger vs. old (on the other ticket). With old vs old, the republicans tend to have the advantage. It's an interesting observation in politics I recently read about.