A lot of nerds would be perfectly capable of installing a different OS. But i atleast often forget that screwing around with the computer itself isnt the focus for a lot of them. They just use the computer to get shit done in their field of special interests. Like for me the whole administrative overhead of switching to Linux was only bound by the resource of time. But i really looked forward to it and had a blast when i finally secured enough time to do it. In the end i just learned a new aspect for my hobby. For others that would just take time away for the things they want to do. Interest in open source, privacy, beeing in control of your digital shit etc also isnt as common as one would hope even for computer nerds.
With that said in the last two years i still saw a big shift. Atleast in the other online spaces i frequent and even in my private life tons of people picked up Linux. Just because the strain of windows became so insuffereable.
kernel level anti-cheat isnt even the issue by itself. most of them work on linux just fine but you can configure them in a way to specifically block linux.