When AT&T ran things, they owned everything connected to the phone network. You leased your phone - you couldn't purchase it. When the telephone answering mac

When AT&T ran things, they owned everything connected to the phone network. You leased your phone - you couldn't purchase it. When the telephone answering machine was invented, you weren't allowed to hook it up because it wasn't an AT&T device. Things are different now. We kind of own our phones, and we kind of have a choice of what goes on them, but who really controls them?