Yeh, but is extremely outside of any manufacturers control for consumer level gear.
For mission-critical satellites or space crafts, then it's either a 3-way-quorum or extremely ruggedised processors specifically designed for the radiation of space (with a massive performance penalty).
It's not something you buy off the shelf. It is a specific requirement that is built in at all levels of hardware, firmware and software.
So, if the steam machine is designed for high radiation environments then it's steams fault.
Seeing as it isn't, a cosmic bit flip that is actually able to impact hardware negatively is so extremely unlikely that it isn't Steam's issue. At all.