That's understandable, and I wouldn't disagree with you on that-- the audience absolutely did widen with the advent of d20. My only question into the cosmos though would be whether learning about other types of RPGs via the d20 umbrella conditioned people to think merely in class-based, leveled gaming? And did that not only cut off people from really experiencing the vastness of roleplaying games, but also perhaps disillusioned them by having some of these games not really work as d20 D&D clones?I don’t disagree, but I will point out that one thing the d20 System and its conversions of various other games did was expose those games to a wider audience. I would probably never have learned of Call of Cthulhu had it not been for the d20 conversion, and while the d20 System didn’t do the tone of CoC any favors, it did make the game more approachable to folks who were familiar with D&D but not eager to learn a new system (which at the time was me).
Also, the sample adventures in that book were awesome.
Obviously none of us can actually answer that, and your experiences with d20 systems seemed to work out really well for you, which is great. I just can't help but wonder though how many people did in fact bounce off of playing games that weren't D&D, because many of the d20 games were just D&D in dress up and unsuccessful dress-up at that?
Now for all I know I could be completely full of horsepucky here and barking up an entirely wrong tree... but with the proliferation of people once again wanting to use D&D mechanics in new games makes me think that perhaps we didn't learn enough from history and we're doomed to repeat it.