According to the StatCounter, Linux on the desktop has continued to rise and remains above 4%, with this being the healthiest it's ever looked on the desktop.
When buying games from Steam, how is the desktop platform counted? From what Valve told us (February 2020), they first take the desktop Steam client platform used to buy it, then whatever has the most playtime in two weeks. However, Android and Web Browser purchases default to Windows and then what has the most playtime in two weeks. If you want to ensure developers see a Linux sale: play it only on Linux in the first two weeks, don’t buy it and leave it.
Found the article.
https://www.gamingonlinux.com/steam-tracker/
Hmmm, now I get it, thank you!