poll is not up yet, but i'll post my opinion here.
i don't now if it is age, as much as circumstances of life. usually, circumstances of life go hand-in-hand with age though.
for example, as i stated in the other thread i just created, my group is 4 guys pushing 40. the other three are married, one has kids. they have other things going on in their lives. dnd is the guys night out nowadays, not the all-obsessive game it used to be. we no longer have 5 hours free time per day to read rule books. by the time you get home, mow the lawn, make dinner, feed the kids, clean the house, and give the significant other a jolly good rodgering, when is there time to learn a whole new game? its easier to just stick with what you know and enjoy playing.
to the extent that age dictates the one's free time situation, then yes i think it is age related. espially with 4e. from what i have ben reading, i don't think there has ever been a more drastic change from one edition to another. all other changs were simple and gradual, relatively speaking. they didn't in essence create a whole new game to learn.