Ma Bell's monopoly has never been "natural". It has been enforced by FCC, ever since FCC was formed for that specific purpose in 1934. Even before that, ICC through the Kingsbury Commitment had adopted an ill-considered and unjustified hands-off policy with respect to Ma Bell's anticompetitive actions.
Jesus, yes, how did I have to scroll down this far before I read "ATT was a government monopoly"? Google doesn't have a monopoly on anything. They have the best search engine, but I can switch in seconds. Likewise the rest of their products all have very well established and really quite functional competitors. That I don't use, cause I like the big G, but I could if they annoyed me too much.
Fact of the matter is that they have a huge influence on the entire economy, and this influence is orders of magnitude greater than any other company.