For me, I typically thought of an RPG as being dead when it was no longer in print. But what does it mean to be out of print in the age of PDFs? I have easier access to AD&D's Oriental Adventures today than I did in 1994. Now I think of an RPG as dead when no new books are being published for it. Someone, somewhere, is playing Cyborg Commando. I don't know why anyone would play Cyborg Commando, scientist and philosophers have yet to answer that question, but I still consider it a dead game because nobody is going to publish anything new. Will it rise like a phoenix from the ashes one day and experience a rebirth? Almost certainly not, but maybe.