I've used Linux since 1997, 15 years, and there have been various ups and downs with gaming on it. MP Entertainment, iD, Epic, Xatrix, Lokigames, S2 Games, Enemy Territory was ported, Medal of Honour. The names of companies that have done things for Linux over the years.
Valve hasn't touched Linux! They haven't done anything for it, barely spoken of it as far as I know. We don't know what was said between Valve and Phoronix, but the person at Phoronix compares what Valve said and its excitement for Linux, to the Linux Foundation. That is not what I would describe 15 years of Valve as being. Linux isn't exactly Valve's priority, they did MacOS first, and now finally a year or two after, they get to Linux. That doesn't sound like the Linux Foundation to me, or even much of a supporter of Linux.
They are a billion dollar company, if they wanted to, REALLY wanted to support Linux, like some companies listed above, they could have done so years ago! 2004 easily I bet without any financial risk.
It's awesome that Valve is going to bring some of it's games to Linux (although Steam can be a nightmare), but they need to walk the walk, and not just talk the talk of Linux if they want to be compared to the Linux Foundation and known as a supporter of Linux, with the apparent excitement that they are talking about, and the influence they have on PC gaming!