[ksk]

Its just a database. Using the registry is not a requirement for any app. They can store their configuration in a text file, they can store it in the cloud, they can do whatever they want, they can even create a C:\etc and store it there :)

Sure, there exist badly behaving apps that don't clean up after themselves when they're uninstalled. Windows gives apps the freedom to choose their own method of installation, but some vendors abuse those freedoms. I don't quite know what the OS is supposed to do about that. Windows already does an insane amount of work trying to keep buggy apps running, something that macOS or iOS or Android or Linux don't. The fundamental goal of any consumer OS should be making sure that the software a user purchased continues to work.

>Android and iOS solve this much better by sandboxing application settings within the app.

So, multiple users on a device = separate settings = multiple app installs? That might work OK for consumer devices, but won't really fly in the IT world.