I think you might be reading a tad too much into it... I'm not seeing the ads as saying, "We don't need the old guys! You'll show up anyways, so we're going after the important people!". You have to remember that for who knows how many years, Star Trek was cool or "accepted" to the general public. It was nothing more than a geek-fest designed for guys who live in mum and dad's basements and have never gotten a girl, as far as the public was concerned. I think the ads are simply trying to say, "Hey, look! Star Trek is cool again! Even you can come watch and not be ridiculed by your friends any more!" And, with a $150mill budget, they really do need to make sure the public is ok with seeing the movie once or twice, or else they'll never make their money back.