In my town, the cable company, when still small and locally owned, relaid its network with fibre-optic cable. I suspect the investment is not that high to do so. Afterwards they jacked up their rates.
As to good alternatives not being available, that's the free market that society wanted by breaking up the Bell System.
Maybe other subscribers do like SBC and there isn't enough demand for alternatives. The textbooks say if people don't like SBC service, other providers will come in to provide it since they'll be a demand for their services.
Some people forget that in the real world, a "free market" is often not what an economics textbook make it out to be. There is no guarantee that you'll have multiple grocery stores, gas stations, or department stores. There's no guarantee that the equilibrium reached in a competitive marketplace is one that we like -- such as the situation described here.
In cellular phones, it seems to me most companies have settled on a $40/month service plan, and it's hard to find something cheaper for occassional users. Theorectically competition should bring that price down, but the marketplace settled on this particular equilibrium, for better or for worse.
I must admit I get frustrated when people complain as in this context. To me, it seems people want the low rates and high service quality of the old Bell System ALONG WITH competitive choices. In other words, they want only the 'good' things about a free marketplace but none of the bad. They forget that in a free marketplace businesses can be jerks. (I believe it was Mr. Decker himself who pointed out how a gas station was not very customer friendly and he had to schlep further down the road to find another). That's the situation now. There is competition and alternatives, but sometimes one must "go down the road" to find it.
People complain today the phone companies aren't too helpful if you have a problem like static on your line. The subscriber must disconnect every phone in their house and check carefully to be sure it isn't in any of their telephone sets, answering machines, computer modems, faxes, or house wiring.
As mentioned before, people once complained about paying $1.00 every month to rent each extension telephone set. But, they conveniently forgot that if they had any problems, regardless of cause (telephone set, house wiring, street wiring, central office, or long distance), one quick easy phone call took care of it. (Back then telephone sets and wiring were built to last forever to keep down maintenance costs and keep service quality high. No longer.)