I suspect that LLMs do pretty well with troubleshooting Linux thanks to those manuals and old forum posts. After using them to troubleshoot Linux based devices, I tried the same thing on Windows and it struggled to figure out what commands to run.
Windows is a mess to configure and troubleshoot, even with the help of LLMs. Microsoft could have spent their investment trying to fix that, but I don't think they have.
"Copilot can troubleshoot your computer" could have been a selling point, but they'd have to admit that windows 11 is a buggy mess