That's like asking why a multimillion dollar company released ffxiv 1.0, an obviously badly designed game with multiple issues. They just don't have the experience or edge in the field that others do as a japanese company with no experience in modern mmorpgs. 2.0+ has roughly been them trying to catch up to the modern MMORPG market from the start.
Their server infrastructure is obviously still incredibly flawed, limitations of not being able to whisper in dungeons, crossworld interactions in general i.e. social lists requiring you to press a button to see if someone is online on another world, limits on what you can do in just about everything involved, the fact that datacenters exist and divide worlds within the same region (NA), etc.
They obviously also care little for reworking content/gameplay/current systems and it's a miracle whenever they do.