Are you promoting some kind of conspiracy theory that Apple is using some people's devices to do inference for other people's devices?
There's absolutely zero evidence of that, and it would be easy to observe it happening. So why are you pushing some kind of totally false narrative?
Maybe there's zero evidence now, but think about the lengths to which Apple has gone to build a private cloud infrastructure and why they would do so. It's one thing for them to offer that as a do-gooder service to their customers, which it certainly is. But once it's established as private and secure, why wouldn't they use spare compute at the edge for inference? It's smart. It's not a conspiracy.