I don't see how that can be true. Valve has made huge strides in pushing Linux gaming forward, and thousands of Windows-only games are playable on Linux, sometimes even with better than native performance.
The small percentage of games that have anti-cheat mechanisms or intrusive DRM (Steam notwithstanding) that are problematic on Linux are likely games that don't deserve my money or attention anyway.
Disclaimer: I do still game primarily on Windows, but mostly because I find dealing with Linux issues (whether that's related to games or otherwise) much more annoying than dealing with Windows' spyware. I can reasonably handle the latter, but nothing is more frustrating than having non-working software when I just want to unwind for a while. I think these are not unsurmountable issues and am pretty hopeful the state of Linux gaming can only improve.
If we are talking about games whose compatibility will increase Linux adoption though, most of those have anti-cheat and DRM.
Edit: I am "posting too fast" it seems (a few messages per hour, I guess?), so here's a response to a comment below here about the mixed-OS household:
I wouldn't mind using macOS or Linux, and I actually would pay if I could install macOS on my PC tower. I might be the idiot here, jumping out of the MS frying pan into the Apple fire, but I find macOS to be just fine for my use, and not too locked down overall when it comes to running the software I need on it and it's very well integrated with some of my other tech stuff. Sure, I can't tweak every aspect of the OS, but I don't mind how it works out of the box so I am cool with that. It would also be nice if I could use some of the macOS features on other platforms, like iCloud, Messages (whatever the blue-bubble messages are called), and iPhone integrations.
Kernel level cheat engines (not VAC) will catch you on a different OS 100% of the time. EAC is vastly more popular for detecting in game cheating, versus VAC which scans the users computer for possible cheats and typically doesn't work well when it comes to preventing cheating if at all.
Many companies invest heavily in kernel level anti-cheat and having to support multiple OS's when the other two big OS's account for less 0.5% of the profit, I just don't see business folk lining up to ensure non-windows users can play video games given the fact it's probably Microsoft making or publishing the game in some capacity.
Anyways, from what I am seeing from tech trends, the future is multi-platform, and it's only becoming easier to code for everything all at once. Smart people are taking time and energy to research things like WASM and APE (which supports Cosmopolitan Libc), not to mention long-running initiatives such as containerization, the various JS engines and other languages which run anywhere, etc. Even with ARM vs x86 happening, software runs cross-platform more and more.
Could change if Linux numbers on Steam hit double digits, though.
I am more optimist than this, mainly because of Valve. They contributed a lot to Linux gaming and are now in a position where they can pounce and steal Microsoft's cake.
Microsoft simply cannot allow themselves to slip up on this anymore and I feel like we are at a point where one more major blunder or a scandal from Microsoft could irreversibly sway the tide towards Valve and Linux gaming in general.
The hoyoverse titles used to detect VMs, but it seems to have calmed down. (I was able to try Honkai Star Rail with no obfuscation effort on my part.) NVIDIA stopped caring about VMs in their GPU drivers a few years ago. FatShark almost made the anti-VM mistake with the new Warhammer 40K Darktide anti-cheat; I refunded the title during early-access and told them why. They reversed course before launch and that also works in a VM. - I've played many Blizzard properties (but not WoW) in a VM as well, though they tend to hate networked storage, for reasons I don't yet understand. (Had to setup iSCSI because my CIFS share over 10Gbit/s paravirtualized NIC was "not good enough", I guess.)
Windows runs in a Hyper-V VM by default now, anyways, so "running in a VM" as a heuristic is of questionable utility to me. (It's how the "Core Isolation" feature is provided.) The real irony is I can't even use the VM to cheat, anyways. The guest's memory is encrypted by default. Modifying it, or even reading it, from the host-side would be prohibitively painful. I guess a VM would perhaps obfuscate emulated/scripted inputs, but I use real devices, and a real USB hub on the guest anyways, because the latency and functionality of the emulated HIDs is awful.
Thankfully Steam is very pro-consumer: if a title I purchase does not run in the VM, or on Linux via Proton, it gets instantly refunded. The nice thing is it is actually in Valve's interest financially to push back on these devs: both to prop up the value of the SteamDeck, and to stop people like me from getting refunds.