You say this like MMOs haven't found other ways to make up the difference (such as microtransactions) and, despite the comparative market saturation since those times making things harder on such projects, mid- or lower-ranking MMOs (in terms of active player counts, insofar as we can know) still having equal or greater profitability than before. We'd seen even since the likes of Maple Story and Dungeon Fighter Online that subscriptions themselves have usually been a lesser driver of profits than alternative means of revenue.