I'd wonder how much Valve has agreed to buy other parts and tooling/manfacturing services. Then they could have scenarios where they have a pile of AMD chips and the rest of the parts, but limited or no VRAM/RAM/NAND to complete the systems so they can be sold, or they've spent a pile of money designing and working with a manufacturer to get to the stage where they can start making batches, but can't get the volume to bring in a real benefit.

Being pragmatic, I wonder if Valve benefit from the health of the PC market, whether they'll also put efforts into helping people get more life out of their existing machines, or individuals/businesses refurbishing to sell on the used market with more confidence. There's already an angle for reducing e-waste with the win10 end of life if it can be tied into installing linux.