The original XBox was indeed a lot like a PC, the Xbox 360 is a bit more... odd. It's running a variant of windows under the hood but it's running it on a powerPC processor (technically making it a Mac
) and it's got a very unusual memory model (for a PC). Quite a lot of 360 code could be re-used on a PC game and a lot of the assets could but some of the fundamental code would have to be rewritten. Ditto the other way - if you took the PC code it might run on a 360 once you compiled it but it would probably run rather slowly and inefficiently. It's not entirely straightforward. Mind you, it's a doddle compared to porting to/from the PS3.
This is all largely bunk though, because these days most games aren't 'ported' as such. Most multiplatform games are written in a rather abstract way, using system libraries that aren't specific to one platform on a development system that takes that abstract code and builds a specific version for each platform. Essentially they write one game and it gets translated automatically to the various platforms.
The business logic the guy is explaining is inescapable though. When the 360 & PS3 were new, the markets were essentially so small that it sometimes didn't make sense to write a multiplatform game. There probably weren't enough sales in the 'other' platform to make up for the loss of funding that an exclusive game gets you - Sony or MS paid a LOT of money initially to get exclusives. It's generally accepted for example that MS paid over $50million to keep the add on packs to GTA4 360 only, so god knows how much they paid to keep Gears of War off PS3. By now, the various platforms have sold enough units that you can pretty much guarantee huge sales on a high profile game. Even moderately successful games sell millions of copies on both consoles. The amount of profit to be made on either platform is now high enough that unless the platform makers are going to pay silly money to make a game exclusive, you're better off not doing it. And the platform producers aren't going to pay silly money any more because they both think they now have a pretty strong catalogue of exclusive content already.
It's a sign of the maturity of the current console generation - essentially exclusive games don't make sense any more unless the platform maker is the one making it.
Jon
