In the USA (don’t know about other countries) the critical long-distance infrastructure that the big telcos use to generate profits was built with tax dollars and government-mandated fees. It was given to the telcos with the understanding that they would maintain and improve it because that would be a profitable and reasonable thing for them to do, and this in turn would simplify government and more efficiently allocate funding from users and generate employment and income for citizens. If rational economic actors were in charge of the telcos, rather than sociopaths or idiots, this would be a great example of how privatization can work for the benefit of everyone.
But of course, the so-called rational economic actor doesn’t necessarily really exist, and the telcos have repeatedly failed to do the most reasonable things for their own best interests and the best interests of the society that supports them, so a good government is likely to have to regulate them to hell and gone, doing things like forcing the sharing of lines to promote competition, &etc.
