Sure, but compare your pipe speed today with your pipe speed ten years ago. I don't think that it's out of the realm of possibility that we will begin to see devices with no local storage within three years.
Take Google Music, for instance. You can have 200 GB of music "on your phone", even though none of it is actually stored on your phone.
and then we also run into contention - the more people wirelessly streaming, the less bandwidth each gets. Add in that with the cloud, there are more links in the chain that can go wrong, plus you frequently get transient outages (instead of the rare catastrophic ones with local storage), and it's not a zero sum game. Some things are fine in the cloud. Some really aren't.
That will only happen when my pipe hits SATA speed.