Many genre writers may feel smothered by the overwhelming effect that a single successful writer may have on a field; in some cases, that writer may seemingly end up owning the entire field.
This kind of success, can actually prove beneficial to those who swim against the tide--once again, Tolkein case in point. One can get a certain amount of notice simply by establishing a fantasy world that is distinctively and actively non-Tolkeinesque.
Of course, there is room in the genre of fantasy for any number of worlds. The process is more clear in other genres. Take Ian Fleming's James Bond novels, which almost single-handedly created and then dominated the spy thriller field in the 1950s and 1960s. There had been novels of espionage and international intrigue before Fleming, of course; writers as great as Conrad and Greene had dabbled in it, and Fleming owed a good deal to John Buchan. But Buchan's Richard Hannay is a far cry from Fleming's cold, competent, hedonistic, jet-setting Bond.
Now, Bond--love him or loathe him, as Frances would have it--and his glossy-surfaced world cast a huge shadow. Not only was he widely imitated, the Bond movies turned him into an imitation, and then a caricature of Fleming's actual creation. The Bond of the books is, despite a certain degree of surface polish, something of a bright thug. (In this regard, the recent "reboot" of Bond in the movie Casino Royale is closer to the original character than the other movies--and far closer than any of the post-Connery Bonds.) There's actually very little gadgetry in the books, and although the Bond of the books is rather chilly and glib, he doesn't use every bullet or bomb as an opportunity for a wisecrack.
One of the consequences of this kind of success, though, is that it creates opportunities for writers who initally define their work by way of contrast. There is no doubt that much of John Le Carre's success with The Spy Who Came in From the Cold is owed to the fact that it is the Un-Bond--unglamorous, downbeat, and disturbingly realistic. Initially publishers would have nothing to do with it; and most of those who picked it up looking for a Bond imitation were either furious or bored. But word of mouth (plus great reviews from critics who were sick to death of Fleming wannabees) eventually gained the book a huge following, and it had a built-in hook: It's a spy novel, and it's nothing like Bond.
Without icons, iconoclasts have nothing to shatter.