I'll actually give you an answer here on why I (just me) think Biden is going to win.
About 40-45% of the country is either Republican or Democrat... Leaving 10-20% being independents.
Now we HEAR every day about Republican that are Never Trumpers. And we HEAR every day about Dems who are "fed up" with Biden and looking to support Trump. IMHO, this is almost TOTAL Bullshit. IMHO 95%+ of Registered Republican and Registered Democrats are going to vote with their party on election...I suppose that a FEW may cross over, but that's miniscule, I think. That means that Biden/Trump are each going to pick up around 40-45% of the vote.
So this election is going to be CLOSE. They always are. Due to the electoral college, the less populated states have slightly bigger influence than they would if we just went by straight up population. That will help Trump a bit... offsetting the fact that Biden will probably win the popular vote. And as usual, Independents like me are going to decide it. Personally, I'll never vote for Trump. Never. That was true even before the 2016 election... I'd have voted Republican in a heartbeat if anyone but Trump was there as I really dislike Hillary. It's the same thing here. I don't hate Biden, but I don't like him either. I'd vote for Nicky Hailey over Biden and wouldn't even think about it.
Now most independents that I know don't dislike Trump as much as I do... But they don't like him either. The fact of the matter is, that if this were ANYONE but Trump, he wouldn't even be in the running for President. The guy owes half a billion dollars for fraud and was found liable for sexual assault. That would eliminate ANY candidate for either party BUT TRUMP. We'll see on this next trial, but he could be found guilty of paying off a porn star so that the truth wouldn't get out before the election. His lawyer did jail time for his part in that already...
I know this doesn't matter at all to his supporters. Trump was right about that... he could shoot someone down in the street and not lose a single vote. But it DOES matter to folks that switch parties based on the candidates. I think that in the end... Independents are going to hold their noses and vote Biden.