Slightly related, but just today I discovered this SteamOS redistribution for generic machines (as long as they don’t have Nvidia graphics): https://github.com/HoloISO/holoiso
Okay, so I read that page and I understand that nvidia graphics are very much a no-go for that distribution. I’m just wondering why? Full disclosure, I know very little about the finer points of GPU compatibility on Linux, but why isn’t it just a matter of installing nvidia’s closed source packages?
Gamescope leans on Wayland features that the Nvidia proprietary driver either doesn't have support for or only preliminary support. It's on Nvidia to catch up. It's not about incentives for Valve, they can't change the driver themselves.
Proton has received patches for Nvidia support in particular, some from Nvidia themselves.
There may be legal issues, Pierre-Loup at Valve (who incidentally recently tweeted about NVK's progress) used to work at Nvidia on Linux driver development. There's a good chance a lot of Valve's employees have signed NDAs too. They've been leaning heavily on partnerships and contract work (like with Collabora, who also host NVK).
Valve want to extricate themselves from Windows, their incentive is to break free from "Wintel". Steam Deck is a priority, but SteamOS is clearly built to extend beyond that and in order to have any success on standard PCs, Nvidia GPUs need to be supported well.