Easily, with all the new updates bringing in new members, it must do. The only way I can see it dying is if membership goes up to like $15-20/month
Jagex said that they would stop making updates for Runescape in 2014, this includes patches and shit. I'd give it 2-3 years after 2014 to die.
Chances are it won't, sooner or later jagex will start a new project and drop RS.

