I do buy the argument that the majority of the shift is due to AI bots / agents. Just looking at the robots.txt I had to implement just to try to keep the majority of bots off my websites is insane (literally 160+ lines of user agents).

But there are some other factors, such as the seemingly steady migration of users from Windows to Linux. I don't buy the Valve hardware argument as much since the majority of those will be used for gaming on Steam, and not likely to be seen by StatCounter or Cloudflare.