WoW could use subs because there was little competition at the time and it could build a large core playerbase. It's much harder to do that nowadays when there are MMOs all over the place, and many of them are free to play.
It's silly to suggest GW2 didn't have subs because they knew it was a substandard product. To believe that you have to ignore the obvious trend towards F2P, and failure of high profile subs games like SWTOR. And you have to ignore the millions of subs that WoW has lost over the last couple of years.