They both were made by, about, and for adult audiences. They both opened well above expectations, at number one for the weekend box office, with $29.4 million and $24.7 million respectively. They both achieved these results with a majority of audience members who were 25 years old or older. Oh, and both of these films had DVD-quality bootleg copies widely available on the Internet months before the wide release date.
So let's play devil's advocate and believe the studios' claims that one of the main reasons that kids aren't going to the movies as much is because they are downloading them illegally online. And let's for a moment acknowledge that one of the main reasons grown ups aren't going to the movies is because the films in wide release are usually aimed at teens and young adults. Let's also concede that one of the main drawbacks of theater attendance is having to view a film aimed at juveniles while said kids engage in all manner of disruptive behavior during the film (texting, talking, walking around the theater, etc*).
Well, in theory, the adults would show up, the kids would see something else and not bother them, and said adult films wouldn't get downloaded because the target demographic doesn't know how or doesn't care to download said films anyway. And since most grown up dramas and thrillers are more cast-driven than FX-charged, the films would be much cheaper to make (and theoretically cheaper to market, since you could concentrate on traditional advertising methods).
I'd argue that the same pattern holds for family films like Paul Blart: Mall Cop, but that's a rant for another day. Just a thought.