I wander if 2K customized the game discs in to groups with Relics that appear more and less often. Like I've never had the Knights Templar, but I have had Atlantis every tiime. It's kind of a crazy idea, but with every on having the same Relics almost every time, it seems like it might be true. Please tell me if you agree of disagree with me.
They might have done this, but I'd be doubtful that they did.
I think it's more likely that there's games where the city of Atlantis isn't there, but people are so use to always seeing it most games they don't realize it and assume someone else must have got it and they missed the pop up from the advisor telling them someone else found it.