There may be non-zero maintenance work happening, but a project that only maintains support for old versions and will never adopt new ones is functionally one that the ecosystem will eventually forget about. Maybe you call that "under active development" but my response is "ok, then I don't care whether it's under active development, I (and 99.9% of other people) should care about whether it's going to support new minor versions."
On the other hand, if you don't support new minor versions day one, but you eventually support them, that's quite different.