except that for a majority of users, windows is where their applications are at - such as gaming, word processing, or some other thing. Sure there are replacements (somewhat) for each of those categories, but they are not direct replacements, and require a cost of some kind (retraining, or a substitute quality). This is esp. true for gaming, and it's only recent that gaming has made some inroads via the steam deck (steamOS), which isn't available to a general PC (only handheld PCs with AMD processors iirc).
People who say "just switch" to linux hasn't done it for their family/friends.
The majority of users either use only web applications, or web applications and Microsoft Office.
The true majority of users are on mobile.
Windows is only unreplaceable for gamers. Which is fine, because Windows is a toy anyway.
And quite a few musicians. When they make my software for Linux - and, it works ootb - I/ we'll be willing to change.