I think at some point 07 developers and community will have to make a decision, either the game stays uncomely for new players, or they change things up in order to attract new people.HD graphics, more end game content, perhaps less grinding would make a game more attracting.Basically majority of 07 players are veterans driven by nostalgia, which is obviously not good for long term.
That being said, without some drastic changes 07 should stay there for 3-5 maybe 7 years.Not sure about rs3 though.