But, that's not what the research was. It was market research - which means that those buying are absolutely the most important part of the research. That might explain why you seem not to understand why they cut off at 35.
If the point of market research is to find out who's buying and what they'll buy, why exclude such a large proportion of the potential market?
But, if memory serves, the survey wasn't packaged as "what are you interested in buying?" but more "what/how are you playing right now?" with a bit of "what/how have you played in the past?" thrown in. And nothing was mentioned about any age cutoff in the survey itself (had there been, I wouldn't have wasted my time filling it out); I didn't find out about that until Dancey released his report, in which it is noted.
Nope. It just wasn't asking the questions that you think that it was. Why on earth would they want market research that didn't accurately reflect the market?
My question exactly: why did they want intentionally inaccurate data that only reflected a particular segment of the community/market?
This wasn't political polling. This was the research (the first of its kind mind you) to determine just who buys RPG's and what those buyers experiences are.
And that's what truly baffles me - it was the first of its kind (of any real significance, anyway) in the RPG realm, so why not start by surveying the entire market just to see what's out there?
Now, all that being said, other than your campaign, which I realize that you play these very long campaigns, what evidence can you point to that this isn't a really, really far outlier?
Must be something about our community, but any significant campaign attempt I can think of run by anyone I've known over the last 35-ish years has either a) fallen apart very early, within at most a few months but often after just a session or two, due to any of a host of factors usually involving available player time and commitment or b) lasted for years.
I somewhat suspect that might be due to back in the early 1e era there being but a very small number of DMs in town, with most subsequent DMs originating in their games (with the process repeating a few times) to start their own, and all of them had a long-term view of things.
Example (I'll file the names off to protect the guilty): the "tree" I'm in started with DM A, one of a very small group of DMs who may themselves have come from a common root, I don't know. His game lasted 6 years in the late 70s-early 80s and produced DMs B and C (of DM C I know no more). DM B's game, which has had three separate campaigns spanning nearly 40 years now, produced DMs D (me) and E that I know of, possibly along with some others of whom I've lost track. My games have gone 10, 12 and 11+ years. DM E's game lasted about 8-10 years through the late 80s-early 90s and produced DM F, whose three campaigns lasted about 12 years between them spanning the 1990s*.
Meanwhile and unrelated, another group in town (who may share a common root, I don't know) had DM G whose game, as far as I know, lasted some 5-10 years in the 1990s and produced for us first a few players and now - as of three months ago - DM H. Thus far these are all 1e-or-close games.
Toss into that mix DM I, who first joined us as a player after some DMing experience elsewhere and who since has had two campaigns: one using 3e that went 11 years through the 00s and a second ongoing PF one that's over 7 years in now.
And sure, one ten-year campaign takes the same time as five 2-year campaigns, and the five will likely involve more people in total. But that's no reason to say we're irrelevant; and around here I'd say we're probably somewhat more of an outlier now than we were at the time of the survey; in part due to game design and in part due to lower patience levels and attention spans.
* - of the people who I know were involved in games during the research period I'd guess about 3/4 would have been aged out of the survey.