Only because the US apparently can't do regulation properly. In the UK, Ofcom regulate properly, and therefore we have plenty of competition and all the forces in place to ensure that the last mile infrastructure company doesn't touch content, allows any ISP to use its services at the same rates, and does its job of keeping the cables working. I can get Internet from any number of providers, all competing with each other fairly on top of this company's cables (and one or two providing their own cables instead).
The thing is, the last mile infrastructure company doesn't run an ISP itself, so it doesn't have any reason to muck it up for the ISPs. That's the key. That's all you need to do - split the ISPs apart from the infrastructure companies.