At least according to Statcounter, Linux is currently at 3.86% worldwide: https://gs.statcounter.com/os-market-share/desktop/worldwide.
It's slightly larger in the US at 5.28%: https://gs.statcounter.com/os-market-share/desktop/united-st...
In India, where I live, it's surprisingly at 6.51%: https://gs.statcounter.com/os-market-share/desktop/india
Take this with a grain of salt, because numbers from Statcounter are not fully accurate. However, none of those numbers are small. 3.86% of the entire PC market is not something to scoff at.
The high amount of "Unknown" is interesting. Especially as it doubled in the last 6-8 months.
Last time I looked on stat counter it showed 4 and something percent. That's where I pulled the number from. But it seems they updated it to 3.86 now. It's so over for the Linux community.
There's also the people like me that couldn't historically run certain games well directly on Linux, so we have Windows virtual machines with GPU passthrough. Which would read as me being a Windows user in the Steam stats, but a Linux user in other stats.
The state of gaming has improved drastically since I started doing it that way, though, and I'm considering ditching the VM entirely. Multiplayer games seem to be getting the hint about anticheat exclusion on Linux. ARC Raiders, for example, is a competitive game and runs flawlessly directly on Linux.