From my perspective, as the author of a handful of unpublished SF novels, the difficulty is that the major publishing houses right now have little interest in producing works outside of perceived "mainstream" genres. The large publishing groups want works that will immediately hit the marketplace and sell 100,000 copies -- and that spells doom for the new SF author.

The reason there are no new "icons" in SF is because the publishers have not given any new authors a chance at a wide audience, and responding with sentiments about "making the novels free" does not cut the mustard because the internet has distribution problems of its own. Just ask John Sundman.