I'd contest where you think the largest portion of D&D players came from. The first wave was frickin' HUGE and no later edition ever outsold what 1e and OD&D were selling in a five year or so period in the early 80s.
We know that in 1989 the
Basic Set sold 1,000,000 copies.
In 1991, TSR stopped producing an all-in-one introductory version of the game and replaced that product with a pay-to-preview boxed set. When the
Rules Cyclopedia went out of a print a few years later, the only true ruleset for D&D became (for the first time ever) a set of three rulebooks clocking in at 700-900 pages and costing in the ballpark of $100.
That remains the case today.
So if there is a problem getting new players into the hobby, it certainly might be due to factors beyond WotC's control. Maybe video games have irreparably harmed D&D (although weren't video games incredibly popular during the '80s, too?). Maybe people just don't play games face-to-face any more (although
Monopoly and its ilk seem to be doing all right). Maybe the game's popularity was entirely fad driven (although it seems to be a fad with an unusually prolonged drop-off).
But I just can't stop looking at the lack of a product like the 1981 or 1983 Basic Sets and saying: "Ya know, the
complete lack of a gateway product might have something to do with it."
And maybe the abandonment of mainstream advertising by TSR (and WotC's failure to re-establish it) also contributes.
Some of us STILL are. I've bounced around dozens of game groups over the years, and EVERY single one of them had a majority of people my age, and I'm 40.
There are a couple of factors here:
(1) Everyone tends to associate with people close to their own age (for a myriad number of reasons). This is just as true for gamers as it is for anyone else. I recently had cause to be exposed to a crowd of much younger people and, unsurprisingly, I was suddenly exposed to a number of much younger gamers.
(2) You're playing a game that's been OOP for 20 years. That's some pretty heavy self-selection bias for playing with older gamers.
That few million players number has been batted around since 2000. There hasn't been this huge drop in player numbers.
There's also been no indication that WotC has ever commissioned fresh market data. It's certainly possible that the number has remained steady. It's also more than possible that WotC is doing what lots of companies have done throughout history and continued using an old statistic because there's no new data to replace it.