Are you really that important?
Get over yourself.
Make irrelevant comments much to try to score debate points?
Who said the world couldn't get by without them? Please point out any post in this thread by anyone that made that assertion.
What people have said is that their families and their careers require that they be reachable 24/7. I can go weeks without receiving an off hours call, but when an emergency does arise, my career would be over if I were unreachable for 3 hours. When I am going to be unreachable due to being on a plane or going to the dentist, I let someone know. This is true of a lot of people.
Many families also have young children. If a husband and wife leave their child with its grandparents so they can go to dinner and a movie, do you think it is wise to prevent them from receiving emergency calls concerning the children? An emergency call that is on vibrate doesn't disturb anyone else in a theater - the person just walks out of the room and returns it.
My grandfather died unexpectedly of a heart attack and my mother was unable to get to hospital in time to say goodbye because she wasn't home when he had the heart attack and cell phones were around then.
Some of you don't care about what goes on in the world around you but many of us do. One of the unfortunate things about emergencies is that they are hard to predict. We don't want to place calls in the theater, but we do want to be able to receive important ones on vibrate mode while enjoying a movie. Is that too much to ask?