There's plenty of rock star coding out there, of course. But it tends to be either hidden inside companies due to secrecy concerns (Google's scaling architecture or the NVIDIA driver stack, say) or exposed in the open source community instead of the startup world (Fabrice Bellard is a great example here).
Startups all say they want rock stars, but then they put them to work doing "better versions" of the same boring stuff we all recognize. Which, if you think about it, is sort of what startups are supposed to do.