Valve’s Tom Leonard explains why there have been no Valve games on PS3 since The Orange Box;

The PC and the 360 are just more straightforward. We can focus on what we want to do, which is make game experiences, instead of sweating bullets over obscure architectural decisions they make with their platform. […] I didn’t come into this business in the 90s because of some technical fetish. I came in because I wanted to give people experiences that made them have fun.

So is the PS3’s architecture is too complicated to program for? Yes but with the quality titles like uncharted and Killzone 2 on the platform is obvious it can produce quality results. This strikes me more that the developers are too lazy to learn it rather than it being too difficult for them to handle. Valve are a hugely talented company and I just wish they would put the effort into porting their games to PS3. Maybe it isn’t profitable for them as they are not the biggest company out there but surely the PS3 audience is big enough to warrant the risk? Either way as a PS3 and Mac owner this really leaves me in the dark in terms of being able to play any future Valve titles let alone Left 4 Dead.

Source;
http://loot-ninja.com/2009/06/09/valve-shuts-out-too-complicated-ps3/