Even for regular users, a big chunk of regular users are looking at other platforms:

- "creatives" have always been a core Apple market and they've grown, so that market has grown; plus, since Windows is globally less dominant, a lot of "Photoshop/video editing software/3D modeling + Windows" folks are now on Macs

- gamers now have Proton + Steam on Linux + SteamOS so quite a few more of them are on Linux now, especially since Valve is pushing in this direction to keep Microsoft honest

- large number of regular office workers have iPhones, especially as you move towards the top of the hierarchy, and are far more tempted than they would have been in the past to try or use a Mac

- in many schools there are now Chromebooks instead of Windows laptops; this is primarily a US thing, but it does pop up in some other places, too

Windows is sort of stable but probably still bleeding users slowly.