The key differentiating factor is that the iCloud heralds an era wherein all of your data is decentralized, all of the time, and that this is the default for all users, on all Apple devices, all of the time.
>iCloud heralds an era wherein all of your data is decentralized
You are correct, for all definitions of "decentralized" that are "rigidly centralized, almost appearing decentralized because centralization is so far outside your control"
Disagree. The key point with iCloud is that the primary storage for all your data is on the device the Cloud is used in the main simply for syncing and messaging.
That's why I like the Apple vision - it leaves my data with me. It doesn't lock it up in a cloud somewhere.
You are correct, for all definitions of "decentralized" that are "rigidly centralized, almost appearing decentralized because centralization is so far outside your control"