Depends on the place. In a lot of countries, the countryside has complete coverage of 3G and 4G. There are also places with at least coax, and even fiber.

In places like the US, companies like Starlink have lobbied so that no cable is installed and no nationwide 3G/4G coverage exists (5G coverage would be near impossible due to the limitations of the technology).

Imho we should be focusing on running cable everywhere instead of trying to maintain a massive network of thousands of satellites in LEO. It’s probably cheaper in the long run, and it doesn’t ruin scientific observations or the ozone layer.