They need to focus on platforms that do "a better job" of looking where Valve want to be in years to come. It would be easier to invest in PS3 if open.
Admittedly this is a little confusing as to how Newell wants the PS3 to be open. Does he mean possibly including support for the likes of Steam? Sony is extremely unlikely to want to do that unless they get a big slice of the profits.
"Platform investments, like the Mac, are difficult because you have to be aware of what direction that platform is moving,” Newell told in an interview. “We need to target platforms that do a better job of looking like where we want to be in a few years.”
On the PS3: "We would love to see the PS3 be more open like a Mac than more closed like a Gamecube. It makes it easier to justify those investments if that were the case.”
The only Valve title to hit the PlayStation 3 has been EA's Orange Box port, which was met with limited success given the trouble it took. Valve has sworn off touching the Sony platform themselves, deciding to stick with PC, Xbox 360 and now Mac.