It feels like cognitive dissonance when the maker of Steam, that is full of DRM and, of course, closed source, talks about the successes of open source.
I mean, I have nothing against proprietary source (the difference between open source games quality and proprietary games quality is giant), but Valve made their living on proprietary code and now they are preaching the opposite.
Valve made it big because they released portions of their code along with the tools to create mods and total conversions of their games. They then hired the most talented people who were using these tools, either pulling them in to work on half-life or to create commercial versions of their own projects.
Then then made it bigger by making it easier for outside devs to publish on steam. Over the course of a decade they worked to turn steam from something that everyone hated into something that nearly everyone loves. The turn around has been incredible; from a hindrance no one wanted to a platform no one wants to do with out.
I believe that Gabe is more interested in Linux because it is an "open platform" rather than it being "open source". Valve were quite happy working on Windows when it was an "open platform" that they could release games onto with out having to jump through hoops. As MS moves to force everything through their own app store, Valve are looking elsewhere.
I mean, I have nothing against proprietary source (the difference between open source games quality and proprietary games quality is giant), but Valve made their living on proprietary code and now they are preaching the opposite.