And yet the root comment claims the opposite (the US is very stretched out, so it’s harder to connect all of it).

In my country, fiber is run to my apartment building and through the technical shafts. Very easy for the telco: to connect a unit, they only need to branch off from the technical shaft. I imagine the total cost to connect 200 apartment units is much lower than connecting 200 farms or 200 houses in the suburbs, even with the red tape.