I'd says the 'Clones are doing fantastic, all things considered. Especially Labyrinth Lord and Swords & Wizardry, which have both gone from fan-made .pdf to print-on-demand, and now into print/distribution in a very short time.
Keep in mind, the success of these has been driven solely by the fans, none of the RCs were created and just dropped into distribution.
I don't consider Pathfinder to be a Retroclone, but rather a contemporary d20 game, not unlike True20, Conan, or others of that ilk, save that out of all them it hews (by design) most closely to 3.5 D&D. I think to truly be a "retroclone" per se, a game needs to emulate a game longer out of print with no real contemperary support. There are games out there I consider to be "retroclones" of Marvel Superheroes, Fantasy Trip, etc, so it's more the out-of-print qualification, or the "retro" element I'm stressing.
Does that mean Pathfinder could be considered a "retroclone" in 20 years or so? Hmm.