It is still the case. It's called Local Loop Unbundling (LLU). LLU accompanied common carrier deregulation in the late nineties. The rules have changed a bit over the years (favoring ILECs) and at's a little more difficult for a CLEC (Competitive Local Exchange Carrier) to get up and running today than it was in, say, 2000, but the rules are still in place.
LLU has been somewhat successful in increasing competition in larger metro areas, though not so much in smaller rural areas There's still significant start-up cost associated with starting a CLEC, and LLU only gives CLECs access to the CO and local loop infrastructure. As an example, a few years back, I was living in San Jose and my internet/telephone was provided by a CLEC at about 1/2 the cost of the ILEC (verizon) who owned the lines.
I've long thought that LLU applied to cable could provide the same sort of benefit. Since the "local loop" in most cases was subsidized (much like the ILEC situation), then the loss associated with LLU is minimal. It allows for increased competition, without forcing it, and gives the opportunity for increased consumer pressure to (because of additional competition) increase speeds/lower costs.