Your building, you say. I can choose between at least two providers in my apartment in Brooklyn, NY.
But somebody in upstate suburbia cannot, and they are lucky if their only provider is not utterly bad.
Density is key here. Suburbia is not dense enough, and is finicky enough about digging or running wires, to make building a competing network lucrative. And the US has a ton of low-density suburban population, even in formally urban agglomerations like LA or Houston.
One solution is to live in a proper city, but proper cities are not very numerous in US, and living there is more expensive.