[waterheater]

Might have to do with demand in those neighborhoods. An financially-constrained person living in a major city in 2024 will have two main choices for an Internet-connected device: laptop or smartphone. These days, the smartphone is the obvious choice. Paying for cell service lets you use the phone around town and at home, whereas paying for home internet is quite restricted.

An ISP usually has a neighborhood hub where local lines connect and feed into the broader infrastructure. I'm betting that ISPs have a pricing model using a "neighborhood utilization ratio" factor, calculated as houses-served-in-neighborhood over total-number-of-houses-in-neighborhood. To cover known network infrastructure expenses (equipment replacement, technician labor costs, etc.), the pricing needs to work out, but low service demand in a given service area for the same infrastructure requires those fixed costs be borne by the few people using the service.

Many infrastructure services typically are more expensive in a rural area, presumably due to this effect but spread over a larger geographic area because population density is lower.