DSL was a colossal failure of regulation. With the line-sharing rules, it was no longer financially viable for the telecoms to invest in infrastructure for common carrier services that they could no longer sell at a premium. Instead, they started investing in wireless. The telcos COULD have invested in FttN and FttH solutions, but wireless became a more attractive investment since it didn't carry the line sharing rules. Thus the telcos abandoned high-speed internet access and the cable companies (which were not under the same rules and could thus justify the investment) became the monopoly they are today.

What seems good for the consumer is not always good for the consumer. See how Verizon halted their national rollout of FiOS and instead plowed $130 billion into purchasing the 50% of Verizon Wireless they didn't already own if you want a very recent example of this.