Given iCloud/Apple logins, though, which authenticates and creates the keys necessary for the Mac to run signed apps, wouldn’t the process of wiping and reinstalling simply include either not deleting preinstalled apps or starting from a state that downloads the apps you need and signs you in/enrols your Mac as necessary? The same would be true for Windows, Active Directory, and any other state required to run the system that has to sync or work with a third-party.
I guess to me that’s what the /persist drive was in the example, the need to customize system data beyond the basic install steps. Think of your Application Support folder, or apps that don’t sync to the cloud, or system kexts you might need to run apps.
The biggest problem isn’t software like Apple’s which use the Internet to authenticate how many systems are in use with generous limits, it’s Software like iLok and such that use various stateful properties of your system in an undocumented way so it’s hard to preserve them across installs. If that software uses timestamps, for example, it might be hard to preserve what it needs. Keychain might be another example, I haven’t fully investigated how that interacts with other chips like the T2 in these scenarios.
The problem is that outside of servers, it can be hard to distinguish between files I care about and files I don’t. What I’m hoping we get in the future is a filesystem and (on Windows) a registry, that automatically containerizes all saved state to the app and user it belongs to, ideally with some kind of historical log metadata. I know it’s asking for too much and would never be perfect, but it’s a nice thought. Right now we rely too much on apps to be well-behaved, but it’s the apps that aren’t well-behaved or that share data between themselves and other apps that are the issue. Apps asking for access is one approach, but I’m less concerned for privacy in this scenario than I am for state cleanup. The trouble isn’t reading anywhere though, it’s when an app shared state by updating data in another “container”, then you’d have to create containers to represent files shared between apps, or the container idea disappears and you’re left with metadata about file usage and global state as an alternative... At that point you’re limited by how much work you want to do to keep the system clean, and it might be easier to identify anomalies periodically than to keep a whitelist updated with files to persist...