Privacy concerns outside our echo chamber are not such a big deal as you imply. To wit, the hundreds of millions of Gmail and Facebook users - I should think the amount of people who are aware of this issue AND care enough to vote with their wallet is negligible. (Not to mention that Dropbox or cloud anything is hardly better, it came out recently that Dropbox employees can look at your files just like Facebook employees can glance at your profile)
I think that even ignoring privacy concerns, theres a quality difference between Dropbox and Google that Google is currently losing.
Our team is only 10 employees, distributed across two offices, but the number of times that I have seen email attachments for docs that were supposed to be synced in Drive multiple hours ago isn't trivial and has led to most of the team returning to Dropbox despite the space limitations. As is, if a doc isn't created in the Google environment (Google Docs, Calendar, etc.) then it will reside in Dropbox.
You say that but yet Microsoft has created a whole marketing campaign around this. It's a humorous to think no one really cares about privacy. I think that is more the kind of attitude in our echo chamber than the other (that no one really cares about privacy).
