I agree with your first three paragraphs to some extent. However the tricky part is that not all rural areas are equally productive, and they don't all require the same amount of investment. Some of the rural investment in the US is highly productive and results in great return via agriculture and/or resource extraction as you point out.

But consider as just one example how much the population working in agriculture has decreased over time - much of that was going to happen whether roads and bridges and power lines were subsidized to go out there or not. When this is private investment, it's fine. If it fails, some company goes bankrupt, life goes on. Unwinding money-losing public infrastructure is much, much harder.

The last paragraph, that renters aren't politically invested, I think depends a LOT on the ability of people to become owners in the first place. Ownership is more the effect of someone who has a certain amount of wealth and stability in their life (thus the resources and desire to own), rather than something that CAUSES wealth and stability in your life.

So as for the idea that "the country was founded on the idea of the homeowner," I understand, but I think we have to be careful not to think that it somehow makes an owner morally superior to a renter. That just leads to discrimination against people who probably would love to own but don't have the resources, and thus don't need the deck further stacked against them.