This whole argument is hilarious. I mean you're comparing an extremely established franchise like Halo, one that is literally built around mass appeal, and is arguably the face of the entire Xbox brand, to some select PS3 games? Not only that but it's all based on some quote that lacks evidence. FPS are also doing far better than any other genre out, and have been for quite some time.
Out of the six games he referenced, two were new IP's, the other two were new installments for older games (GoW 2 came out six months prior to Halo 3 even released, that's how long it had been...). Did I mention that God of War has historically been a very modestly selling entity, despite having a cult following, and some of the highest critical ratings/receptions of all time? That says something....
It's just funny to pick the highest selling game on your console of all-time, then compare it to some random, although good games, on another console.
LittleBigPlanet, God of War 3, Metal Gear Solid 4, Heavy Rain, Resistance 1, Uncharted 1/2, Killzone 2, Motorstorm are all amazing games. Just because they don't dwarf the sales of one of the most over hyped/rated franchises in the history of gaming doesn't mean they're inferior.
I mean MW2's sales were disgusting, and it was vastly inferior to its predecessor. That really says it all about the validity of sales figures.