As noted, the key to Biden's dominance of the race so far, and Trump's inability to dislodge him, has been Biden's ability to cut into Trump's 2016 margins among white noncollege voters, the demographic Trump was depending on to get himself re-elected.
Morning Consult recently released data from a variety of swing states that, among other things, break down the race in each state by white college/noncollege. Here is Biden's current performance among white noncollege voters in the consensus top six swing states (MI, PA, WI, AZ, FL, NC) with Biden's margin improvement relative to Clinton 2016 in parentheses, as estimated by the States of Change project .
Michigan -6 (+15)
Pennsylvania -13 (+19)
Wisconsin 0 (19)
Arizona -7 (+18)
Florida -21 (+13)
North Carolina -33 (+17)
Pretty impressive eh? It's very interesting that improvements are large not just in the key Rustbelt states but also in the key Sunbelt states. It continues to amaze me that this isn't a bigger part of the narrative around the election when the data are so damn clear.