Speaking of Debbie Downers, welcome. What are your reasons Biden is going to win other than voter fraud?
1. Polls - I think they are likely to be more accurate this year. There are many reasons for this, the most important being weighting by education. The aggregate polls are showing a consistent and enduring 8-10% lead for Biden, as opposed to a 4-7% inconsistent lead for Clinton in 2016.
2. Low (less than 45%) approval ratings for POTUS.
3. Biden generates less animosity than Hillary Clinton, even among Republicans. He is consistently polling better among whites and particularly white men compared to Clinton.
Of course, a lot can change between now and November. The polls are a snapshot, not a predictor. If the polls are the same in late October as they are today, a big if, I am confident the GOP, led by Trump, will be obliterated in the election.
The shy Trump voter is an ameliorating factor in the above equation. There is no way to know how big this factor is. It would have to be of an unprecedented magnitude (6-8 million votes missed by the polls) for it to be dispositive.