piped.video/watch?v=KW6E51xXcWc for Valve’s contributions, by a KDE dev. According to a 2022 interview they pay over 100 open source developers working full-time on various important open source projects, from Mesa to Vulkan to AMD GPU drivers to KDE Plasma to gamescope to Wine to DXVK and VKD3D to you name it. The whole desktop ecosystem is benefitting from this, not just the Steam Deck, and not just gaming.
I get that proprietary software and DRM is a general problem, and Steam is part of that problem, but completely getting rid of that is simply a battle for another time, further in the future. The first battle is to get Windows users abandon their Microsoft/Apple cages, and that’s a win that’s actually within reach now. Windows also becomes worse by itself, further accelerating the change. That’s important, because running a proprietary OS is still much worse than running some proprietary applications or games on a free OS. A closed OS completely shifts control away from the user, leaving only what the developer allows you to do, and it allows the dev to always push his or her agenda by favoring applications from the same developer, and allowing the developer to establish proprietary APIs and libraries like DirectX which was problematic for the competition for quite some time. Establishing Linux as a neutral, user-controlled, non-proprietary, much more trustworthy OS is the first step away from that. And to reach that, users will have to be able to run at least some of their usual applications or games on Linux as well. Otherwise they simply wouldn’t switch in the first place. For a regular user, using Linux cannot feel like being a downgrade. A regular user does not understand the ethics behind closed and open source and will never choose a worse free option over a better proprietary one. That either means the free options must become true rivals, or - which is the easier goal for now - the proprietary apps have to run on Linux just as well as people are used to.
A “war” isn’t being won all at once instantly, but by winning several smaller battles after one another. Which takes time.