The September 2023 numbers for the Steam Survey were published a few minutes ago and put Linux at a 1.63% marketshare, a 0.19% dip compared to the month prior. Granted, on an absolute basis the Steam on Linux marketshare may be doing well depending upon the month-over-month growth rate of Steam overall... The September numbers meanwhile show macOS losing another 0.14% and now down to 1.43% while Microsoft Windows has a dominant 96.9% marketshare.
When pulling up the Linux specific numbers, the Steam survey shows SteamOS Holo -- the OS powering the Steam Deck -- as losing 1.14% marketshare to Arch Linux gaining 0.4%, Ubuntu 22.04.3 LTS ticking up by 3.58%, etc. As for why the Linux percent receded, the Steam Simplified Chinese use picked up by another 5% this past month that tends to correlate more with Windows users. It also wasn't until the end of September that Valve released Counter-Strike 2 and provided a native Linux build for gamers interested in CS2.
Further confirming a decrease in the Steam Deck percentage of Linux gamers is AMD Van Gogh as the most popular for Linux gamers pulling back by 1.16%. But the Van Gogh APU still holds a strong 43% marketshare among Linux gamers.
On a CPU basis, Steam Linux gamers still are 70% with AMD processors to Intel with 30%, driven in large part by Steam Deck owners.
Those wishing to comb through all of the September 2023 Steam Survey numbers can find the latest data at SteamPowered.com .