Sites do often die. Sometimes it's because after years of being around, they get no traffic. Sometimes it's because whoever owns it just doesn't want to do that anymore. Sometimes, as with GBA-Source, it's because the server dies. Usually you can sense a sites death coming on. It's a slow process where the members start constantly bickering, the owner never comes around, and a few people become elitists and adopt a holier-than-thou attitude.
Hmm, sounds familiar, doesn't it?