This is actually a great point. I've taken some esoteric issue with my Debian Linux install and gotten exactly the needed fix. Especially when the error is extremely misleading ("/dev/root: Can't open blockdev" was that I forgot to install the actual kernel image itself...) Distros could ship open-weight LLMs that sure, might take a minute to come up with the answer, but they could be preset with the privileges to actually execute the solution.
However, those only exist because real people talk about problems on forums. If we fully integrate an LLM into the desktop and nobody discusses the issues they run into anymore, will LLMs continue to be able to solve the problems?