Yea, I could probably list a few hundred examples and you could probably shoot each and every one of them down on an individual level. Great. The larger point is that in the aggregate, there are enough individual situations that would be disrupted by jammers in the theatre that it would outweigh the nexus between the number of times someone is going to be inconvenienced by a conversation during a movie and the number of times someone is actually rude enough to pick up the phone during a movie. At the end of the day, it's a cost-benefit analysis.
If a movie theatre did in fact install jammers each parent concerned about their kid (yea, it's probably not a true emergency, but subjective perception matters) or each doctor (I'm thinking more about delivering babies, which can mean being on call for weeks at a time, than an ER doctor) might choose to skip the movie. The end result is that that the theatre will likely take a hit on their profits. That's not a compelling reason to invest in installing a jammer.
The whole "we survived just fine without constant connectivity" argument is flawed. Yea, we did a lot of things without modern technology. We got along fine without movies, driving to the movies, mobile phones, the Internet, or arguing on the Internet about the need for mobile phone access during a movie.