Dungeons & Dragons, elves vs. elfs, MERP, role-playing games
The reasons for this disparagement of Tolkien’s influence on D&D, and thus ALL roleplaying games, are I think twofold. First, there’s the simple fact that Tolkien’s innovations are so great that they have, ironically, come to be considered “generic.” In fact, they only appear that way because the genre of Modern Fantasy is something Tolkien himself largely created; he is the exemplar that defines the category. The very idea of a player character party — a group of diverse individuals of differing races with differing talents and specialties who set off on an adventure together — is a uniquely Tolkienian innovation, unprecedented in earlier fantasy, where we either have a hero, or a hero & a sidekick.
In other words, Tolkien influenced fantasy and gaming so profoundly that we take his imprint on other authors for granted. His impact has become invisible — just look how many people spell “elves” and “dwarves” with a ‘v’ rather than “elfs” and “dwarfs”; “elves” may be partly due to Dunsany, though I doubt this, but “dwarves” is Tolkien’s invention, which others use without even recognizing their indebtedness.