1. Airplanes are loud. A person on a phone could disturb one or two people, maximum.
2. In flight entertainment. You can listen to music, watch movies... If you don't have ear phones on, expect to hear people. Heaven forbid you over hear one side of a conversation!
This craziness isn't brought on by technology, it is brought on by people use to being alone in their car. Now they are next to people... talking!