- Tolkien’s ascendancy was not inevitable. It’s really a fluke that he even became the template for the modern fantasy epic. A half dozen authors would have easily been considered on par with Tolkien in the seventies.
- Our concept of “Tolkienesque” fantasy has little to do with Tolkien’s actual work. Likewise, the “Lovecraftian” stories and games of today have little to do with what Lovecraft actually wrote. Our concepts of swords and sorcery have had the “weird” elements removed from them for the most part. Next to the giants of the thirties, just about everything looks tamed and watered down.
- Entire genres have been all but eliminated. The majority of the Appendix N list falls under either planetary romance, science fantasy, or weird fiction. Most people’s readings of AD&D and OD&D are done without a familiarity of these genres.
- Science fiction and fantasy were much more related up through the seventies. Several Appendix N authors did top notch work in both genres. Some did work that could be classified as neither.
- It used to be normal for science fiction and fantasy fans to read books that were published between 1910 and 1977. There was a sense of canon in the seventies that has since been obliterated.
There's more at the link, and the comments are actually worth reading. Go there, and when you're done read his blog posts on those Appendix N entries. You will be better for doing so, both as a gamer and as a SF/F fan.