It's difficult to compare Dropbox to Apple, Google and Microsoft in terms of what they offer and for how much. All three of those giants are able to subsidize their storage offerings. Apple has their hardware business, Google has their ad business, and Microsoft has their software business. The storage offerings from all three are used to entice you into using their other services. It doesn't matter if they're profitable (and I'm willing to bet that they aren't). What does Dropbox have? Nothing but its storage offering.