That day may still never come. Seems like a rumor at this point, and consider the source-- Phoronix is well known in the Linux press for hyping rumors.
a. Steam on Linux is still in beta and relatively new
b. Cutting-edge triple A titles? No, not yet. Older, but well seasoned triple-A titles? Getting there (e.g., Team Fortress 2, Left 4 Dead 2). High-quality indie titles? Quite a selection, actually (e.g., Minecraft, Humble Indie Bundles, etc...).
