Recently, I came to realise that Drupal is not a community platform any more, it has grown into an editorial tool over the last years. Sure, you can build a community on top of Drupal, but the tools to do so, are underdeveloped, stale, or even simply unfinished.
I see more and more high-profile editorial sites being build, and see fewer successful or high-profile community being released.
Not that there are no good examples of Communities built on Drupal, there are! But their amount is so small that they hardly count.