Nothing Trump or the Republican Congress does will help rural Americans. It'll likely help megafarms and other big businesses but that won't translate to the little guy in the country. The question you need to ask with that make them turn on Trump or will they believe more of the lies? If you look at Wisconsin with Walker, the rural areas are hurting now more than when he was elected in 2010 but they still strongly support him since he's still against the "evil city Dems".
There's something deeply, even if not overtly, nihilistic that's wormed its way into the rural/small-city white American world-concept in recent decades--I say this as a rural/small-city white person. I have my ideas about why this is, but I'm increasingly at a loss as to what can be done about it, especially since I don't think doubling down on making American economic life a constant hunger games to move to and survive in one of a few big cities is an acceptable option either morally or prudentially.
I imagine a true infrastructure bill with apprenticeship/retraining of blue collar rural workforce into skilled trades would go a long way to help. Plus eliminating farm subsidies for large/mega farms while increasing it for the small family owned farms.
But then you have one side not wanting to do anything of that and saying "if we do this it's socialism/the black man will come kill you all" and they fall for it.
Edit: I have friends in the country that think if you go into Milwaukee you will be mugged and shot to death as blood runs red in the streets. Yes, crime is up in the last two years but people don't go around murdering randoms in the street like they think.
