Optional app sandboxing that does what you're talking about already exists on every major OS, disregarding Linux distributions that don't have Flatpak. Seems to

Optional app sandboxing that does what you're talking about already exists on every major OS, disregarding Linux distributions that don't have Flatpak. Seems to me it's less a UX problem and more cultural: a critical mass of developers take the easy way and users learn to ignore the alerts. Android has the same problem with the "all files access" permission. The one platform where this works, iOS, has a totalitarian ruler that requires all apps to be sandboxed and not request gratuitous permissions. To really get around the culture problem you would need an OS that lacks the concept of undeclared data sharing between different packages.