Valve may have contributed to the issue initially, but can you blame them? There wasn't exactly an abundance of Linux Support before Valve came along either. Why would they support a Linux Steam client and the whole compatibility layer when the demand just didn't exist.

Valve becoming big enough to break into the hardware market (first Steam Machines and then the Steam Deck) was the first time they had any incentive to care about the OS layer. They could've made some deal w/ Microsoft but instead went the open-source route to the benefit of everyone. Kudos to Valve.