Dropbox had a great claim, originally, that your data was secure not even "dropbox" could see it. Well, it turned out that was a lie.
The bigger issue is privacy protection. If I upload non-public information to one of these services, which one can I trust to keep that private? If there is no clear answer, then price is the only differentiator. Who's going to protect your privacy when presented with an NSL? Answer: no one. After that, who cares?
I believe that if a storage company wants to stand out and charge a premium, it needs to hire lawyers, a lot of them, to defend the rights of its customers. When you store your data on your property, you are protected by the 4th amendment, the warrant requirement, and the legal right to a defense, when you store your data in the cloud, you have little, if any, protection, and the service provider has no duty to protect your data from government requests.
Criminals, lawyers, and the general public have the same needs. If you can't protect criminals, you can't protect the general public. Data storage has never been about the bits. It has always been about the meta requirements: security, longevity, recoverability, and yes, cost. The google/amazon threat is about cost, what about the other requirements?