Also, I’m not sold on early D&D being “standard fantasy”, because of stuff like gygaxian naturalism and, uhm, Greyhawk being so stupidly complicated (for reasons I do not have will to explain).

Late d&d iterations and standard fantasy became progressively closer, to the point where there’s an expected canon. I also blame Tolkien, but not JRRT, just the fact that he’s often seen as the only “literally non-garbage” fantasy worth reading.