I think your hitting on "inclusion" is pretty accurate.
Older, Caucasian, unskilled or poorly skilled, moderately educated, living in economically depressed areas of flyover country, nobody's been listening to these guys. Their demographics and the America they once knew are slipping away from them, and what they used to do isn't working anymore.
They're not included in the financial success coming out of the economic crisis. They can't relate to much of the news and entertainment beamed in from the coasts. And they can't relate either to the growing urban environment and centers. The GOP & Dems ignored them. They watch their small towns and rural areas lose their young people and children to the cities they can't relate to.
Trump is going to put an end to the foreigners that take the new jobs, and he's also going to bring back their old jobs. He'll give them a voice in Washington again, and remake the old America for them.
Yeah, they'll belong again.
And, I can see the draw. Even if they don't really believe it will happen, they'll probably be happy enough someone is claiming to try to help them. Nobody else has, for a very long time.