Windows 11 not working on otherwise perfectly good PCs I imagine is at least a small part of it. I've got an 8-core Ryzen system I think from 2016 that's still very powerful and more than good enough for my needs, but Microsoft is insisting I "throw it away and buy a new one", in this economy no less!

I also think a number of influencers like PewDiePie moving to Linux has to have moved the needle at least a little as well.

For me it was Windows 11 not supporting hardware. I moved to Fedora in the beginning of this year for work (while using it at home for quite a while).

After seeing SharePoint.exe using 1GB and 100% of the CPU today for over 12 hours I’m seriously considering removing my VM (that I only boot for MS Office). Edge even greeted me with a message that I have access to Copilot Vision that can now see everything I browse when I right clicked the process and clicked on search!

It's conceivably part of the reason.

Earlier reporting on Windows MAU noted "400 million Windows PCs vanished in 3 years" (https://www.zdnet.com/article/400-million-windows-pcs-vanish... ). As Windows 11 wrecks havoc on older PCs, many may just sit unused or get discarded, thereby increasing the relative share of the surviving PCs (including Linux PCs).