In Apple's case, they have complete control over iCloud and could offer this easily for any file which is stored there. They could also add some sort of metadata API so services like CrashPlan, Backblaze, etc. could register the presence of other copies in a generic manner. Third party services could also integrate background scrubs into their existing application.

In each case, the first time that dialog appeared you'd likely have a customer for life from anyone who's gone through the hassle of losing a personal memory, important document, etc. or make a panicked search for other/older copies.

Also, I wouldn't be surprised if Apple adds a cloud-based backup for macOS once APFS is the default filesystem, since change sets would be extremely efficient.