But it HAS worked for Trek. Trek has got young actors and put them in space. You know, comparatively. Being in his late twenties (and with his character as 25 in the movie) Chris Pine is the youngest actor to ever play the leading role in a Star Trek production.
What more do we need, Star Trek Babies?
Well, depends on why it is that you believe Trek made so much money.
If you believe that it was mostly kids who went to see the film, then, yeah, I guess shoving a bunch of pinup models into the roles probably had the desired effect.
On the other hand, if you believe that it was the action and the special effects, then the age of the actors isn't important. Look at the Indiana Jones and Die Hard films, for example. Ford and Willis aren't much younger than Shatner but their respective movies in 2008 made a ton of money.
I personally think it was a combination of the two, though I don't know how well that bodes for the longevity of the new leg of the franchise.
As I've said before, I, personally, thought the story line of this last movie was extremely weak. It relied heavily on special effects and a story that only worked because every person who saw it already knew what to expect by the end of the film (in stark contrast to the entire purpose of the film, but, I digress).
Action movies are great fun and frequently do well for an installment or two. To have any kind of run beyond that, though, you need characters you can identify with and strong story lines that keep you wanting more. Neither really existed in the last film and only time will tell if it exists in the next.
If, on the other hand, it's the pinup models they put in the roles that matter, then I probably wouldn't get to used to any of the current actors as they'll probably be replaced before we ever get to know them.
In either case, I don't see any of these current actors playing these roles a decade down the road, let alone four of them.