Don't read rust belt voting based on how they feel about red vs. blue. They have a completely different orientation to their thinking.
They want someone who will chuck a metaphorical grenade into the halls of power. That's why they voted for Trump. That's why they will not vote for a candidate who can be described as "safe", "stable", "reliable", "familiar", or "acceptable."
Trump did not start out in the lead and march to an expected convention nod. The GOP convention saw not just the usual whisperings of backroom jockeying to have the voting sewn up by the time the big moment comes, but a verbal brawl over rules changes from the "Never Trump" holdouts.
So the angry people see their own plight through Trump. He may not be one of "them" but he earned it by playing by their stupid rules and then they tried to steal it from him anyways. The old guard, the hacks, the people who keep selling us out tried to stop him, "so he must be on my side, or at least he'll give the ones who engineered my deprivation some what-for!"
For the life of me I can't find what program I heard it on recently, but someone was explaining that a lot of how we grapple with voting is in the part of the brain that is associated with social reasoning and much more "simple mammalian" than "advanced primate" kind of thinking.