and finally the 'Microsoft tax'
The article is about the lack thereof, unless you're referring to some patent royalty.
Valve is gonna have is the same problem 3DO did.
But not quite so much because the other console makers have caught up in price. The first commercial Steambox will cost $500, the same as an Xbox One. Hopefully by then, Radeon drivers for SteamOS will have caught up.
but since Valve isn't making the hardware they're not _subsidizing_ the hardware.
If an operating system is a component of a computer system, then Valve is subsidizing development of this component.