For the urban, and dense suburban areas fiber is a great option and has much higher potential. But there will always be a large portion of the US that is not profitable to run fiber, and already has phone service. We already have multitenant access in the US for all phone service. Just extending the current regulation to cover DSL is all that is needed to allow for competition and improved internet speed. You can get up to 76mbps with VDSL2 over copper wire, just modern modems and provider side equipment. And there is newer technology that provides even better speeds over the same copper wire.