They are losing users to Windows 10: thousands are removing Windows 11 from their computers that came with it and instead installing the last version of Windows 10 in its place
https://tekniikanmaailma.fi/windows-11-sai-kyseenalaisen-kunnian-menetti-markkinaosuutta-windows-10lle/Since 2021 all new computers are shipped with Win 11. But that doesnt necessarily mean the new computers are incompatible with Windows 10 version 2022 which was the last Win 10 version released in late 2022. It is indeed a bit more recent than first version (the initial release) of Windows 11.
Win 11 user base has fallen through january 2024 to april 2024 by 1%. From 22% to 21%.
Meanwhile Windows 10 users increased from 69% to 70%. From this we can only fathom that it is Win 11 users removing their Win11 from their computers and installing Windows 10 in its place.
Amount of WinXP and Win7 users did not change during January to April, only the amount of Win10 and Win11 users did. WinXP and Win7 make total of 3% of computer users which is not very big amount.
The rest are Linux users. Using Linux subsystem for Windows in Win10/Win11 is not counted in Linux userbase.