I think you are talking past each other because you are not talking about the same party when asserting whether there is or isn't a problem. It's true that the investors don't have a problem if Dropbox fails to live up to its valuation. Venture capitalists expect that most of their investments will fail. But a company that has accepted venture capital is beholden to its investors and will almost certainly have a problem if it fails to live up to their expectations. Remember that investors are part owners, and get to make decisions about how the company should be run. The more dissatisfied they become, the more drastic the changes they will demand.
