I recently saw Carl Malamud [1] speak, and he said straight out that for his projects it has generally taken a decade to get somewhere. From his descriptions, it sounded like the first years were mainly him being ignored, but that eventually his continued presence meant people with power started paying more attention. His advice to the crowd was definitely to pick projects they'd be happy to spend 10 years working on.

[1] http://en.wikipedia.org/wiki/Carl_Malamud