I'm curious what Mac OS X is lacking that Valve needs to port their games to OS X. What does Valve need that Blizzard, id Software, Epic, etc can get by without?
Maybe these other developers just have more talent on their staff. After all, we haven't heard about any of those developers having their
source code stolen, either (For those not in the loop, the Half-Life 2 source code was stolen in October, 2003 - a year before the game was released. Apparently the same hacker broke in 6 times, utilizing different exploits each time).
I'd suggest Valve just doesn't want to invest in developing for OpenGL, but I imagine the PS3 port of The Orange Box uses OpenGL, so I can't explain their issue now. Either way, I seriously doubt Apple is to blame in this case.