I would guess that nothing happened to them, and that they have never been used to store encrypted iCloud data. Apple has an enormous amount of data that needs to be stored beyond iCloud: iTunes, App Stores, Apple Music, etc. I'm sure they store much of that data in-house.

There is also the possibility that Apple eventually plans to move iCloud to their own storage solution, but hasn't yet scaled up to it yet.

> iTunes, App Stores, Apple Music,

Would it really require a datacenter to store that small amount of data?

They don't have to relay purely on one solution. It would make sense to host certain parts of their infrastructure on GCP if enough of their customers are also located on GCP.

I guess they use these and the cloud services in conjuction. There should be an Apple technology that abstracts the specifics away.

There should be! Any serious consumer of cloud storage has an abstraction layer that let's you store new data in arbitrary locations on site or across public clouds. Companies frequently write their own middleware connectors.

Aren't those for music and videos?