Until Jagex shuts it down(unlikely) or when the higher staff decide they don't want to pursue an RSPS or can't afford to anymore.
I was wondering about this. Have big RSPS's been shut down lately by Jagex, does that happen at all? I reckon local law enforcement has to get involved to do that, seems kind of a hassle to me. It is esentially just free advertisment for their game since I don't feel like a lot of people who play RSPS's would play normal RuneScape.