I think Biden will win for one simple reason. Let’s cut through the mountain of BS and analysis.
40%+ of folks are going to vote just as they did last election because they’re loyal to their party. Only the undecided folks in the middle really matter – that’s like 10%-20% of voters (probably closer to 10%). This is not news.
Very few of that “middle group” of voters who voted for Trump are sitting around thinking, “Wow, I’m glad I voted for Trump – he turned out to be really good.” So, of that middle group that voted democrat last time, almost all of them will do the same this time. But… a large percentage of that group that voted for Trump last time aren’t going to do so this time. And that will be the difference. It’s not that complicated. As with everything in economics, everything important in politics occurs at the margin.
I don’t know how close the election will be, but I think the odds of Trump winning are extraordinarily low – it will take a miracle (eg, massive Russian interference).