If you have seven friends, that is 49 units of code, not to mention that if you want people to call you, you have to memorize your own personal code. I live a busy life. I don't have hours after I come home from work to sit and memorize these codes. Telephones simply aren't fun. Yelling is fun.
Nothing gives the kind of immediate gratification that yelling does.
There is nothing more soothing than a set of rapidly oscillating vocal chords. The Government, that's who. It is an ingenious plan. Telephones are all connected by wires that run from inside your house to outside where they are strung up on 30-foot wooden poles. The wires are so high up that you can't see what's going on up there.