Only 2% of Users
Puts some context into Valve’s decision to drop Mac support from SteamVR.
VR is definitely very small, and at 2% of the Steam userbase is clearly not a huge market. That said, there are other slices of Steam users that are 2% of the pie as well: Mac users.
Yes, Mac users account for 2-2.5% of Steam users (Steams survey results are not always up for some reason, but the numbers are replicated here), which is actually down from 10% back in 2010 when the service was newer on macOS. Considering last fall's macOS Catalina update decimated upwards of 80% of people's game libraries, you can see why the Mac isn't a major destination for gamers.
So if we say 2% of Steam users have VR headsets and 2% of Steam users are on a Mac, how much do we think those overlap? Given that there is basically nothing to do when it comes to gaming with VR on a Mac, I'd say it's likely Windows users are 10x, or maybe ever 100x more likely to have a VR headset than a Mac user. That leaves what, Bob who accidentally ordered one from Amazon and hasn't gotten around to returning it yet, as the only Mac user with a VR headset?
I love macOS. Really, I love, love, love it, but it ain't for gaming, and certainly not for gaming in VR in 2020.