It's hard to say how things would have gone differently, but I don't think it would have been much different. Looking at the ISP world today long after the dust settled, it's not that much different from the Bell era in terms of consumer choices. I have one choice in ISP for my address. A de facto monopoly entrenched by a lackadaisical attitude towards expanding infrastructure connectivity.
As I said, our problem was that we stopped holding monopolies to account. The Bell breakup was a last major success of the old approach to monopoly regulation. The reason you have one ISP is not the thinking that brought you the Bell break up, but what came after.
