An august 1-2 poll of Michigan voters, 44% Trump, 44% biden, 8% other, just 5% undecided. It's unlikely they'll all split Biden, and even they disproportionately did, a Trump win would still be well within the margin of error.
Biden isn't an unknown quantity. Trump isn't an unknown quantity. Voters know what they stand for by now, they know what they'll be like as president. And yet it's still close.
Let's put it this way, I admire your optimism if you assume Biden will win easily.