I think that this statement probably was "more true" in the regards that KZ2 would demonstrate, to non-PS3 owning gamers, what the PS3 was capable of, and make it an appealing gaming option.
In a sense, all he's really saying is that Sony is working hard at building an impressive lineup, which showcases their own platform, and isn't failing to do so -- KZ2 is merely the latest such example.
Any and every game could be "the one" the sways a potential buyer into purchasing a console. I wouldn't touch a 360 with a 10-foot pole until Lost Odyssey showed up, as a personal example. Then I had to have one, because yep, I get LO, and Mass Effect, IU, Fable 2 (and BC Fable 1, which I never played), etc. etc.
To say LO was the one game that motivated me to score a 360 would be false. Yet, it played a role. I think that all this guy is saying is that KZ2 is yet another one of those games that people will list off, when they say "I bought a PS3 because..."