They don't care.
Lag is very bad and some of us are cut out altogether from endgame.
There's this thread:
http://forum.square-enix.com/ffxiv/t...-fix-something.

Not a single meaningful answer. Just a post from a mod that shows they are NOT EVEN READING (or ignoring the elephant in the room and giving a fake answer to not address the issue, which is more likely).
This issue is what will kill the game.

Oh, and WTFast, Pingzapper and Battleping and other similar programs don't do anything noticeable for me.