I'm more confused as to how it's an old adage. While in general it is a truth, it isn't as if it is something said for a long time.
The generalization is that an Xbox 360 exclusive, in the same year, sells better than PS3 exclusives in the same year. There isn't a single year, that I'm aware of, where a PS3 exclusive sold better than an Xbox 360 exclusive.
No one, that I'm aware of, would go so far as to say that the PS3 doesn't sell games. That's a bit extreme. That being said, Xbox 360 games, even if you eliminate the units sold on PC or PS3 where exclusives become or are multi-platform, sell better on the Xbox 360.
This generalization as applied to third-party multi-platform titles applies just as well. The majority of third-party multi-platform titles sell better on the Xbox 360 than they do on the PS3. The exception to this is FIFA, Batman, and there's one more series, but I can't remember it.
If you own a PS3, what does it matter? If you like a game, why does it matter if it sold more or less than the same game on a different platform? It doesn't. Sure, it's a notch in Microsoft's belt that in general they sell more games per console than their competitors, and it's fodder for developers to consider, but I don't get why it's such a big deal to gamers.
The PS3 is going to, at times, sell exclusive games better than the Xbox 360 will. Likewise it'll sell third-party games better than the Xbox 360 will. If people haven't figured out by now that the Xbox 360 and the PS3 are essentially equals, than you need help. If you're more interested in waging console wars when the two can go tit-for-tat with each other, than you seriously need help.







