You are right, that isn't the correct analysis. Initial programming editors like EMACS, vi, EDIT, TECO, FINE, SOS, and KED tended to keep cursor motion and edit commands bound to key combinations that would be available on most (if not all) terminals. This minimized the use of "special function" keys, even if they were there, because they weren't there for all terminals. So the working set of keys was smaller even though the keyboards themselves were of nominally average size.

My observation was around the use of the PC's special keys used in "generic" editors because the authors of those editors have chosen to assume that everyone it typing on a keyboard that matches, or emulates, the 101 or 108 key keyboard that the PC made standard.