Since moving to Chicago, I've made a lot of younger friends, simply because I work with a lot of people 27 and under. Not that such a thing influences my musical choices (if anything, interference users have greater impact on that), but it helps give me glimpses into the thought processes of those younger me, albeit from a small sample size. But I don't think I could make younger friends if I myself did not have a mindset that jived with theirs. I mean, there are certain viewpoints and thoughts that only experience can shape, but the foundations of how I think are still in place, and those foundations more closely resemble the thoughts of a younger crowd than my own peers, especially in the professional environment I inhabit. To be fair, the advent of Facebook or LiveJournal lends itself to a sort of myopic point of view that I don't always relate to, as I'm a bit global in my thoughts....and while not immune to self-analysis (I suffer from it, if anything), my world never has and never will revolve strictly around me.....so there is that occasional gap. But overall, I've not reached the point where I relate with the married with kids and a mortgage mindset. That's why my age blows my mind, but, that's a whole other topic and I'll spare you.
So, while their lyrics do not resonate with me quite as powerfully as they resonate with you, IYS, they certainly hit home in many instances, and that would help explain my affinity for the band. There's a wisdom there that belies their age, and there's emotion to be felt throughout, at least for me.
As for age impacting art, I find that to be a confusing phenomenon as it pertains to music. I know plenty of people my age who listen to 80's music only, and that's fine, I guess. But, it's not like they only watch 80's films, or read only 80's books. Their tastes in film, TV, literature, if it exists, has not stagnated. Music seems to suffer more from this than any other artistic medium, and I don't really understand why. The thrill of "discovering" Los Campesinos, The National, Okkervil River, TV on the Radio, Fleet Foxes, Elbow, Doves, etc, over the past few years is something I'll chase for many years to come. And, yeah, as I grow older it's possible that I'll be challenged to relate to the lyrics, but that has yet to happen.
Hope that makes sense.