Depends on your time zone as far as activity. It sounds like you're logging on at the dead of night for all of the American time zones or just logging into a dead channel.
As far as if the game is being shut down, all games face that chance and always, technically "will be dying." Grand Fantasia has came a long way and was indeed endanger of completely losing its core player base quite a few times over the years. But recently as what happens usually, the GM team stepped in and worked with the community for a better outcome of the game.
So no, as of now, the game is not in danger of being shut down. However, in a longer view, yes. All games are.