Having Kirk and Spock in the new films gave it the hook it needed to gain audience attention.
This is a just-so statement, and I doubt that it's really the case. The hook needed to gain audience attention was the return of the Trek brand, period. Only fandom gives a shit about what characters are helming it, the general audience does not care.
Successful and largely forgotten in the public eye.
That sounds like wishful thinking to me? I'm pretty sure the public eye remembers Picard and crew perfectly well -- they had more eyeballs during their run than any other crew -- and it certainly seems over-hasty to be pronouncing them obsolete in pop-culture terms. In fact I wouldn't be overly surprised to see them rebooted at some point in the future, given how thoroughly they got gypped on the big screen. (I mean, who can say. The one thing I've learned about any incarnation of Trek by this point is never to count it out in the long haul.)
That's not at all true and betrays an extremely shallow viewing of the two films.
Tell you what, how about we just agree to disagree on that one and simply stipulate that, owing to youth or different conception or alternate timeline influence or what-have-you, the characters in NuTrek are quite deliberately different from the classic characters (whether or not one still finds them compelling, yes?). NuKirk (likeable and charismatic though Pine is) is not personally someone I would follow on a pub-crawl, much less into a situation of life-or-death, but even if you disagree about that, the fact that he is a vastly different character from Kirk should not be in dispute. And that is my point.
They just want to see some space adventures and be told a halfway decent story.
If that was even remotely true, Serenity would have been a monster hit.
Serenity did not have the accumulated reputation and goodwill of the Trek brand backing it, so that's a false comparison. In fact it's arguably an example of the hindrances faced by a show and concept that, unlike Trek, really is dependent on having certain characters present and on the audience relating to and understanding their dynamics. A lot of Serenity would not have made sense to audiences outside Firefly's small cult base for just that reason (and the additional problem that the parent show aired for like six episodes before being cancelled); and Trek owes its long-term success to not suffering from that hindrance, precisely because its brand had the opportunity to grow beyond just being about one set of characters.
The new franchise owes a great deal of its success to its dynamic and likeable cast, and there is some nostalgic fun to the notion that Karl Urban is updating DeForrest Kelley and so on. That's not an indication that "Trek is Kirk and Spock and Bones" and nobody else. If that were true, replacing Bones in the core trifecta with Uhura would not have worked. Right?