There's many extensions hosted in Gerrit by Wikimedia that Wikimedia don't maintain or "care" about. Often, but not always, people update these extensions whilst they're updating Wikimedia extensions. This is extra maintenance burden, when we don't have spare time or capacity.
We use this as our benchmark for "removal" after deprecation purpose (can we remove this from core? is it used anywhere). Should we be doing this?
Long deprecated code sits around in core, because of unmaintained extensions still using it. If no one else cares about it, why should we? Why should this be a blocker to removing things from core?