Yep I think you are right.
If that was series one, I think the Pop Idols would have been Chistmas number one, but the public have wised up a bit and not as many feel that they want to rush out and buy something just because it won a lot of votes on a TV show.
I guess from Cowell's experience, everything first released from these shows (apart from One True Voice) was number one. He and others must have assumed the same.