I get what you're saying, but Dropbox is not a back-up service. The distinction is that Dropbox didn't exist before Dropbox. There are unique aspects of Dropbox that were new when Dropbox was introduced.

There is nothing new or unique in what you described, with the exception (maybe) of automatic initiation of VPN services when you're on "public" wifi. I would argue that this is a differentiation of little or no consequence, because there's no reason to not use a VPN all the time.

You basically described every personal VPN provider in the market as a start-up idea.