Ma Bell wasn't created naturally at all. It's monopoly status was granted by the federal government. This is fundamentally different from Facebook, Amazon, etc. If anything, the large ISPs like ATT, Verizon, and Spectrum should be looked at, but solving the problems of ISP monopolization will take a lot more than just breaking up territorial monopolies into smaller territorial monopolies.
Why does it matter whether a monopoly is "natural" or not, let alone that the definition of "naturally" is sort of laughable given the legal framework put in place for our government is the economy in the first place? Just as you get a lot of government run monopolies with pure socialism, you get a lot of "market-driven" monopolies with pure capitalism. Both should be broken up.
The point is that they're caused by different processes, and the steps to ensure that it doesn't happen again after you break them up are also very different because of that.
The US also broke up Ma Bell in 1956, forcing the spinoff of Bell Canada and Caribbean operations, and before that in 1925, breaking off other international operations into ITT.
https://i.imgur.com/rMFqmbt.jpg
https://www.motherjones.com/politics/2019/03/att-time-warner...