In the UK our situation is much better, although BT owns most of the physical cable "Local loop unbundling" forces them to share their lines with competitors.

It seems in the US the only people you can buy from own the physical infrastructure. Once one company has already built their network in an area they form a natural monopoly - it's not economical for competitors to come in and rebuild the network when they know they'll only be able to get a certain % of households to switch.