That leaves the unwashed middle, call them independents, perhaps moderates, certainly the non-affiliated. Those basically peeved at both parties and how both parties govern for only their base and not America as a whole.

I think you are projecting your own studied independence on The Independents. I bet most of them have little awareness of politics, and just vote for celebrities or the snappiest dresser. Those who think a lot about political positions and lament partisanship are a very small minority. Lots more sports fans who would rather watch ESPN than PBS. They are easily manipulated by demagogues like Trump with "simple-but-wrong" catch-phrases. Trump had to practically destroy our democracy to lose their support. If he had been just a bit less blatant, he would have won in 2020.

We're flying electric helicopters on Mars yet you can't turn on your clothes dryer in Texas. That's because scientists are in charge of Mars, and Republicans are in charge of Texas.