Phoronix article: https://www.phoronix.com/news/Steam-Machines-Frame-2026
Also listed here: https://store.steampowered.com/sale/hardware
Valve has already sent support for the new Steam Controller upstream: https://www.phoronix.com/news/New-Steam-Controller-SDL


It is also very hard for them to do marketing selling third parties modular parts, it’s much better for them to come up with a product.
If you want to replace parts in your computer so that it doesn’t became useless in 5 years or end up in a landfill when a piece break, build your own SFF