Originally Posted by Shrimp
Thing is, it's evident they've already started a Steam client for Linux. Why not tune it up and finish it? You're saying no one on Linux would buy games, and I'd agree that not many would but you'd be surprised. I know people with SLi setups that run Linux for some strange reason. I bet they'd make more money from Linux users than they are from making mountains of DLC for TF2.
Because, as I said, skilled labour is hugely expensive. From the screenshots, Steam for Linux was no where near completion. It might take a few months for a stable release and when you think about a team of say 5 devs, you're probably near Â£50,000 alone in pay for those staff. That doesn't include other costs associated with a build.
As for games, 99% of Linux Steam users will have come from Windows. It's not like Mac where there is an untapped market. If you're a gamer, you'll have Windows. Majority of folk will have already purchased their games and remember, it is up to developers to make non-source games Linux compatible (will they bother to do that)? So the only guaranteed revenue stream is from Valve games that folk pay for.
It might not be worth the up front investment.