Earlier quoted context omitted.
just to be pedantic, the valve devs are absolutely open source contributors, they just happen to be paid to do it.
It's great that Valve is willing to pay them for it. It's a bit sad that such capital investment from a commercial party is necessary, but I can live with that. As someone who has just switched to Linux gaming, I've got to say it's working great. Maybe it's slightly less stable, but not by much, and performance is excellent.
In order to do something big, many people must invest many resources, and they would only do so if they all see great value in the thing.
In order to have resources to invest, all of the people must have excess resources that they have generated from previous endeavors.
Remember, capitalism is merely the most efficient system we have for assigning limited resources across society.