It's important to understand that most people are absolute niggercattle who think installing an ad blocker on their browser is a bigger inconvenience than wasting thousands of hours of their time on ads over the years.
Windows definitely had a decline in quality internally, post Windows 8.1.
8.1 kernel wise was pretty solid, they introduced some nice new cache aware locking primitives, introduced NonPagedPoolNx. It might have also been the last version of windows to offer a completely checked build, can't remember. Also maybe it was before 8.1 but they added the minifilter driver type which solved the issue of 3000 nested filesystem filters blowing the kernel stack
Since 10 though there has been a huge decline.
The 20000 new UI frameworks they add end up breaking legacy programs. case and point balloon tip notifications used to show an ico properly sized. If you enable bitlocker on win11 you'll see a pixelated toast notification whereas in 10 it's fine.
Also... Enabling info level logging in windbg, why the fuck do windows drivers spit out verbose logging in their release builds.
Rant over lol