Don't they already? Not to sound a jerk but respecting others is the only reason people are expected to not be yelling on a plane. You shouldn't talk on a phone during a movie at the theater and for the most part this is a non issue that society ad hears to out of respect for others. Taking a flight to Miami during spring break will probably not be the quietest flight you have taken simply because most passengers are gearing up to party and they out number the norms of society at that moment. But your other flights are mostly quiet because everyone has pretty much agreed that talking loudly on a plane is rude and therefore don't engage in this behavior. Why should we treat cell phones differently? I would think most people would text anyway.
Kids crying on a plane doesn't really bother me because they are kids. By all means, as a parent please try and have some control over your kids by setting an example on how they should behave but people getting angry at kids whose world is so small and who don't know how to control their feelings and emotions is ridiculous in my opinion. Kids grow up just like we all did, mostly. As a society we will always "suffer" through their growth. I try and push past my annoyance and actually enjoy trying to figure out their behaviors at these times and think back on the stupid things I use to think were such big problems when I was a kid. I'm sure I pissed off plenty of adults in my youth. I am in a public place with tons of people operating on different time zones and I can't really expect kids, teens, and adults to respect my wishes so I need to adjust my outlook on these encounters and prepare for them. /me puts in earbuds.