But if they're required to actually spend money upgrading infrastructure (outside of areas with mean income above $500k), they won't be able to make the same kind of obscene profits they do now.

Have you ever seen San Francisco internet? It's awful in many populated places and mean income is quite high. I get a gig pretty much anywhere I live in a big Texas metro area.

A good point; I didn't mean to imply that they would always upgrade infrastructure where income was high. Just that they would try to avoid it by any means necessary where income was lower.