Pretty much have to agree with what Aegis said. There are workarounds and things you can do to compensate as a player, which a lot of us have figured out how to do in order to keep playing the game, and can share with each other to help make it more playable for everyone.

However, this doesn't make the way the game works acceptable or good by any stretch of the imagination. And it definitely doesn't make it people's ISPs' "fault" when it's only an issue for FFXIV and nothing else. People saying otherwise also need to remember that this game is available on PS3 and will be available on PS4, and there's much less you can do to fix problems there. A well-coded game compensates for most of these differences in connections, and doesn't result in nearly as many people having problems as there are playing FFXIV.