Here in dense NYC, most apartments I've lived in have but a single ISP available. It's common to hunt for apartments by searching the address on service maps.

I'm pretty sure one landlord was cut in by his ISP, as he skipped town when I tried to ask about getting fiber, and his office locked their door and drew their shades when I went there with a technician on two occasions. The final time, we got there before they opened and the woman ran into the office and slammed the door on us.