Secondly, data isn't unlimited. It hasn't been for a long time. Even those on "unlimited" plans have limits and throttle points. If you rely solely on mobile data to access your cloud music, for example, you'll probably burn through your monthly data limit very quickly. We're living in a world where cloud usage is being increasingly encouraged, but data usage is being increasingly throttled while cost continues to rise. These two facts are simply at odds with one another, to the detriment of consumers.
It's also dubious to have your phone only be useful if it's connected to the Internet. There are times when a connection to the Internet won't be available. What about those times when you travel overseas and don't want to pay for massive roaming charges? One could argue that these predicaments are a couple of the reasons why Google's Chromebook concept hasn't gained much traction. At the end of the day, there is a lot of value in having core content available locally, while using the cloud only as an extension -- not as a crutch.
Samsung has even been giving buyers of its flagship products a whopping 50GB of Dropbox storage space. While this is most certainly a generous offer, it's usefulness hinges on fast broadband access. If you can't access the Internet, what good does the cloud do for you? If you're constantly hitting your data limit, how frequently are you going to seriously rely on the cloud?
There's nothing wrong with having one's cake and eating it too. Cloud storage is fantastic when it's available and works, but as phones and tablets increasingly become primary work machines in a lot of on-the-go instances, being able to rely first on local storage is paramount. And it's something that I fear is being looked at less now that the cloud is the buzzword du jour. Yes, select Android phones allow you to bolster your storage with a microSD card, but that's not an ideal solution either. In my view, there's still a very real need for fast, reliable, internal storage to continue growing in mobile devices.
Does everyone need 128GB or 256GB in a phone? No, but so-called experts also figured that under 1MB of RAM would be enough memory for desktop systems "forever". With apps growing larger, one could conceivably fill up a 64GB phone with those alone, and something tells me we just aren't in a place to rely on the cloud for everything else. Not yet, anyway. Oh and as the saying goes "back-up early and often" folks. Trusting your data to the Cloud or your fragile handset is like walking a tightrope without a safety net.