It appears that Valve aren't stopping their push to improve Linux gaming, as they just recently hired another developer to help improve open source graphics drivers.
The new hire is Tony Wasserka, a programmer with a lot of experience. Looking over their resume, Wasserka previously worked for the likes of Imagination Technologies where they worked on the Vulkan driver for PowerVR graphics chips. Additionally they also help to found the Nintendo 3DS emulator Citra, they're a contributor to the GameCube and the Wii emulator Dolphin, they also contributed in the past to the Wine compatibility layer and more. It's pretty safe to say they know their way around some complicated code.
It's settled: Going forward I'll be working with Valve on improving the state of open-source graphics for Linux, starting with the RADV AMD driver!
Note - RADV is the Vulkan driver for AMD GPUs with the open source Mesa drivers.
Considering all the resources Valve are putting into Linux gaming across a number of developers to work on the actual graphics drivers, the ACO shader compiler, the Steam client on Linux, the Linux Steam Runtime container system, working with CodeWeavers on the Proton compatibility layer for Steam Play and more they must be pretty confident in their plans for Linux gaming as a whole. No matter what, everyone on Linux ends up benefiting from all their work since it's largely open source.