Valve are super-big on PCs. They've made their name on the platform, and they love it to bits. But what about the Mac? Unlike other big PC names like Blizzard and EA, Valve's titles never see official Mac releases. The reason? Apple can't seem to get their shit together:
... they seem to think that they want to do gaming, but there's never any follow through on any of the things they say they're going to do. That makes it hard to be excited about doing games for their platforms.
I bet it would! Mac fans, as hard as this may be for you, you're going to have to blame great mother Apple for your platform's Half-Life deficiency. Gabe Newell Valve Interview - Orange Box [Kikizo]