So watching it unfold last night I see part of why he won. It wasn't really about politics and the Dems underestimated the impact it would have: Inflation. CNN overlayed a map of where inflation hit the middle class the hardest and it was a lot in the closest battleground states - not in the big cities; mostly rural areas. Those people went out to vote because they think Trump will somehow help with that and they are looking for change and they tend to vote red. Trump won't help with that, HE was the one who sent the country into that downward spiral in the first place. Yeah, Biden sort of kept it flat, not really improved, but that's what happens when you're handed a dumpster fire.
Dems got lazy again, thinking it couldn't happen. One party is too dumb to realize they're being lied to and the other is too dumb to do something about it.