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.
Most of its secret sauce is either in Proton or upstreamed into Wine, DXVK, SDL, etc. All available to a general PC.
Unless your focus is competitive online games, which often come with Windows-only anti-cheats, you've got a huge catalogue of great games playable on Linux distros. I did the switch about four months ago and I'm not missing Windows, the only pain point has been Nvidia drivers and I'll be solving that by switching vendors.