Another consequence of D&D being dominant acurred to me this morning: because people treat D&D and RPGs synonymously, they assume that the history of D&D is the history of the hobby. That is too bad. There is so much more to the development of the hobby over time, and D&D has hardly ever been a leader in innovation, even if has usually been a leader in sales.
For those interested, I heartily recommend Shannon Applecline's Designers and Dragons series of books. There is a ton of great historical information and just interesting anecdotes in those books. The audio versions are even well done, if you, like me, are stuck in the car a lot.