core.logic has been in continuous commercial use pretty much from its inception, and that continues presently. I'd argue that calling a continuously high rate of change a prerequisite towards usefulness is an attitude which makes more sense in communities where there's little respect for backwards compatibility and thus a high rate of bitrot, ie. Ruby.
There's been maintenance commits regularly (2 days ago, 20 days ago, etc) and the project itself is stable. So while there's been no new features added, I don't see why that would be necessary if it works well as is.