the US is notoriously unhealthy, you noted this before. Even the rural areas you mentioned dont have access to healthy unprocessed food. This the pandemic occurred on top of a diabetes and obesity epidemic that was already present.
What you describe could possibly affect the mortality rate, but it shouldn't affect the R number so much, except in the case of "unhealthy" management of food. Eating out is likely more common in the US than here, and that will affect the R number.
At least here in Washington State, we require them to be worn in all businesses, and most seem happy to comply.
Masks become pretty redundant if social distancing is observed, of course. And when/if distancing is not observed, masks must also be handled and worn correctly, or they might make things worse. I don't think the unwillingness to wear masks here is political. It's just felt awkward, and perhaps somewhat rude. Similarly, there is a debate over whether it's ok to cover up the face in public for religious reasons. It's considered somewhat rude not to make your face visible when communicating with others. Interestingly, during this work from home period I've seen the same thing in video meetings. Norwegians tend to feel it a bit rude to insist on video mute, whereas other nationals find it somewhat inconsiderate to expect video from others, as many people don't have the best home office situation and being on video becomes pretty intrusive.