Well said but by the time mobile phone towers were built we had been tapping phone lines for a long time. Hard to not think that to an extent default insecurity for telecoms was a choice.
I worked in a company that had a base station emulator in their testing lab in 2008. I can’t recall the cost but it was well over $10,000 and only worked with direct antenna coupling, it couldn’t broadcast.
Now we have software defined radios.