It's important to note that the ASF did say no to Wave. It never made it out of the Incubator, because it was unable to build an active user community.
And in addition, simply by virtue of going through the Incubator at all, these projects ensure that the source code is available under a well known, well understood, popular, ALv2 license - and the code, email archives, and other artifacts that were created are preserved by the ASF even when the project is sent to the Attic. This is still a net good for the world in general, IMO.
And while it's not exactly common there have been forks of Attic'd projects outside of the ASF that went on to be useful to people.
And while it's not exactly common there have been forks of Attic'd projects outside of the ASF that went on to be useful to people.