Valve just released a FAQ on Steam hardware.

Basically, things are rough going because of the RAM crisis. So the Steam Machine is not going to be super cheap. And the shipping might be delayed.

However, there’s also good news: both the SSD and RAM are serviceable and upgradeable. So when storage and memory prices inevitably come down—and they will—you can upgrade.

Steam Hardware - Steam Hardware: Launch timing and other FAQs - Steam News

Answering some of your most-asked questions about Steam HW

(store.steampowered.com)