Internet providers need to be subject to competiton

Major cities in the US have far LOWER population densities than many major cities in other countries.
The following list gives people per square kilometer, for some reason:

Seoul/Incheon
16,700

Taipei
15,200

Madrid
5,200

London
5,100

Tel Aviv
5,050

By contrast, Los Angeles–the most densely-populated American city–ranks 90th in the world at 2,750. New York is 2,050. Dallas/Ft. Worth & Houston, with about 8 million residents between them, are 1,150.

Seoul is 6 times more densely-populated than LA.

In other words, your cavalier dismissal of population density is wildly incorrect.