- Their Snapdragon X laptop didn't do very well, and they likely realize an ARM Windows laptop will always be a second class citizen: https://www.techpowerup.com/329255/snapdragon-x-failed-qualc... .
- Likewise, Mobile SoCs are completely dependent on Android without proper upstreaming (which they haven't done in the past).
- They are seeing Valve spending time and money on FOSS support paying off, especially with their new hardware releases.
On the other hand, proper upstreaming of the chips give them much more flexibility for different linux-based OSes.