Since Congress broke up AT&T and created the 8 ‘Baby Bells’ the natural monopoly has been dissolved and the Market took off from there.
Every company that has emerged since is still regulated due to their use of radio frequencies and FCC regulated lines.
These diverse companies profiting from the the usage of our ‘airwaves’ are hardly monopolies.
You have most things backwards. It was the government that created and protected that monopoly and prohibited competition. Meanwhile Bell Labs invented every core technology needed for computers and the internet. The market took off in commercial aspects, but cell phones and other tech was already done by Bell decades earlier.