Guild Wars 2 has sold plenty of boxes, and according to lead designer Isaiah Cartwright those boxes are translating to long-term players after all. In fact, Cartwright told Polygon that the game is experiencing growth in both overall and concurrent players after launch.
While the game did experience a population drop after launch, Cartwright stressed that this was entirely normal and something that every designer should plan for. He declined to give hard numbers on player growth, but he did state that the game's current update plan came about as a result of looking at the game's metrics and determining what players were more likely to log in for.
Guild Wars 1 is also apparently maintaining a solid number of players, and while the game is in maintenance mode, Cartwright states that it's in no risk of shutting down.