Whilst the idea that single-player gaming is a gimmick is clearly taking the point too far, I think there probably is some merit in what he says. I mean, I've been playing Company of Heroes for 6-7 years now, and I certainly wouldn't have done that if the only antagonist available was the AI (because the AI is stupid). Pitting yourself against people gives a much more even, much more difficult game. Sure, that's one particular RTS, and it does not apply to all games, but there's something in what he says.