Community of whom? Active developers or passive users? Development and usage of a product are not the same thing. ^_^

Yes, it has grown, and now it is going flat. Try to visualize the trend - imagine a bell curve (the only type of curve hackers know) and point out where the current time stamp is - on a growing or falling slope? ^_^

OK, to look a little bit more professional: doing a major rewrite of already mature project is a tricky thing (look what a terrible mess Gnome3 is or a recent Ubuntu), because users are passive and tend to use what they call a stable versions.

We can see the same situation with Python3 (although it has real improvements and much less buggy) and with ruby19, where the Rails guys are pushing it as hard as they can, but inert users still want 1.8.

So, users are happy with drupal6 and variety of third-party modules, while independent developers are losing their interest.