It pretty much comes down to identity politics. We don’t just vote for politicians who promise us stuff… sometimes we vote for them because of who they are and who they allow us to say we are. In the case of rural voters for Trump, there are large trends that are making rural life in America far less appealing for a lot of older white Americans.
Companies are fleeing, shops are closing, their kids are moving to places with more opportunity. Their values are increasingly shunned as immoral. They feel inferior intellectually and socially. Immigrants, who work harder for less, and don’t necessarily speak English are moving next door. Because of Netflix, movie theaters are closing, because of Amazon… the local shopping mall (that was barely hanging on by a string) is closing. The kids that remain have nothing to do and are getting hooked on opiods. In other words, it is a culture in decline.
Trump comes along and says he’s going to make America Great again for people like you, “Oh no, it’s not your fault… its the Mexicans’ fault.” “Yeah,” he says, “it’s okay to be a little racist. And I gonna yell and scream and get those companies to move back to Iowa (or whatever)…. and I’m going to put conservative supreme court justices on the court that will think the same things are gross that you think are gross.” In other words, Trump is affirming them. “I am going to stick it to those coastal elites who look down on you and your latent racism, your religion and questionable values.”
Largely Trump has held true to that promise. not because he has succeeded at anything. He hasn’t. But no one doubts that most decisions he makes are only designed to help his base or hurt their perceived enemies. He makes these Americans feel smart and put upon and like a cohesive group and that’s worth more to them than any actual policy that might stand a chance of making life better