I personally think a major issue is he may have over-stretched in terms of the repos he sought to create and support as a maintainer. He has 140 public repos many of them significant. As his interests, shifted I have experienced that the pace of reviewing and responding to comments and pull requests became really slow and ultimately led to frustration among contributors as well.
Might have been better to clearly prioritize and state which repositories he planned to support and which not and possibly either hand over ownership or mark the repo he didn't intend to support as orphaned.