Which leaves us with the RC release candidate Announcement:

    After a five year hiatus we're back with a GitHub organization, with new admins and new maintainers who have brought a great deal of energy to make a long-awaited and long-needed new release.

and the 1.7 release Announcement:

    It's been almost five years since the release of jq 1.6. Recently we have had a great influx of contributor and maintainer energy. We now have 12 maintainers (up from 3), with about 4 or 5 active maintainers (up from 0), we have 8 admins with several active admins, and several owners at least two of whom are active. As a result the project will not again have such a long hiatus.

Either any dirty laundry is well buried or (more likely) this was simply a case of the original implementers hitting some plateau of achievement and fading away leaving JQ to eventually be picked up by others.

Others would have to chime in, I have nothing I can add.