They were also very right about one critical point:

> without charging users for the service, is it reasonable to expect to make money off of this?

Dropbox was initially pitched as a free service, which was absolutely not sustainable, and someone would have been right to be very skeptical about the underlying business model. People might not have been quite as enthusiastic if they'd said from the beginning "oh, and it'll be $100/year for the rest of your life, or until you get your shit together and move your data elsewhere".