Actually it does try to reconnect if there's a blip in your connection you just don't notice it as easily in this game. In FFXI the send/receive numbers are constantly visible onscreen. In FFXIV they only appear if you mouse over the connection icon. You'll R0 usually well before you completely disconnect and you'll notice that gameplay seems to stop for a bit. A hard disconnect that seems instantaneous is likely a loss of upload data from you to the server as opposed to no longer receiving data from the server. You're still getting the data from the server so the game seems to be working fine when in reality the server is getting nothing back from you. It waits for a few seconds to see if it gets data from you then terminates your session.