Celebrim - any sales figure data to support your argument? GURPS is a tough place to reason from because there are so many variables. With too many variables, I would say it would be fairly easy to pick and choose the facts to fit a number of different arguments.
Also - what exactly is IP? One of my uneducated options about this is that DnD continues to hold onto gamers because of some fairly basic ideas and a sense of familiarity. Magic missle, vorpal blades, drow elves. These tiny things, taken as a whole, are probably as significant as more grandiose ideas like Dragonlance. Whether or not the small things constitute IP in some legal sense, I think they create a culture that is familiar and sought by gamers.
Finally (and I save the best to last) - please comment upon the "Network Theory of Usefulness" as it relates to RPGs (and I'm making this term up from some half-remembered idea of someone elses). The "Network Theory" says that an items usefulness (in this case an RPG) is related to the number of OTHER people that also own the item. Ie. a telephone is only as useful as the number of other people that own telephones.
IMO this plays a huge part in the popularity of DnD. The bulk of the players in my current campaign joined because they had heard of DnD and that I was running a game. They were gamers that had played some other systems, but had I been DMing something obscure, I wonder if they would have been as comfortable. I'm pretty sure, all things being the same, that they would have chosen a DnD game over another one. So I think popularity breeds popularity. That's my gut feeling as to why DnD has managed to survive some pretty horrible product IMO.
Also - what exactly is IP? One of my uneducated options about this is that DnD continues to hold onto gamers because of some fairly basic ideas and a sense of familiarity. Magic missle, vorpal blades, drow elves. These tiny things, taken as a whole, are probably as significant as more grandiose ideas like Dragonlance. Whether or not the small things constitute IP in some legal sense, I think they create a culture that is familiar and sought by gamers.
Finally (and I save the best to last) - please comment upon the "Network Theory of Usefulness" as it relates to RPGs (and I'm making this term up from some half-remembered idea of someone elses). The "Network Theory" says that an items usefulness (in this case an RPG) is related to the number of OTHER people that also own the item. Ie. a telephone is only as useful as the number of other people that own telephones.
IMO this plays a huge part in the popularity of DnD. The bulk of the players in my current campaign joined because they had heard of DnD and that I was running a game. They were gamers that had played some other systems, but had I been DMing something obscure, I wonder if they would have been as comfortable. I'm pretty sure, all things being the same, that they would have chosen a DnD game over another one. So I think popularity breeds popularity. That's my gut feeling as to why DnD has managed to survive some pretty horrible product IMO.