People are constantly changing directions, and constantly trying out new things which may or may not be useful to them in the future. We're all better off if that code gets released. In turn, we can't expect people to support code they may no longer use, or may not have ever really cared about in the first place.

It should be clear that running an open source project is something completely different. If you make an attempt to start a community, you probably should keep up with that community, or at least responsibly exit it. But people usually build communities around things that are really important to them, or that they have an ulterior motive for advocating (not necessarily a bad motive, just one beyond pure open source).

From where I'm sitting, if Gruber isn't adding anything to the community, he should have been made irrelevant by that community.