I have to disagree with you on this. D&D isn't a game (or at least it's not solely a game), it's a brand. I'm not telling you anything you don't know when I point out that OGL games can't use the D&D brand, or even mention it. Even the biggest of the competitors (Pathfinder) doesn't get the shelf space at Barnes & Noble, Wal-Mart, Target, whatever, that D&D does despite currently outselling D&D through other channels. If the D&D brand is mothballed, I do not take it as a given that other RPGs will be given the vacated shelf space, and even if they are, they aren't D&D. Not every new gamer is either spawned by another gamer or introduced to the game by other gamers. I'd be surprised if even a majority were.
A 12-ear-old kid who's heard about D&D and goes to Wal-Mart looking for it, and doesn't find it, but instead finds all this "Pathfinder" stuff -- what's this kid going to do? D&D is a presence that other games aren't and never will be, and it has influence beyond what it puts on the shelf.
And yes, I can keep playing my Pathfinder or CoC or whatever, but I'm not the issue. The hobby needs the thing called D&D to be front and center or new people will not come at anything like the rate the hobby needs to sustain the production of new, quality material across a broad range of games.
Frankly I just don't believe there are hordes of 12-year-olds flocking to the stores to buy D&D. In the first place, where did they hear about it? In fact I think that the reason we are seeing 5e is exactly because there aren't enough 12-year-olds filling in for the loss of those who left WotC D&D.