It's one thing to blame Amazon and Google for a price war. But DropBox's pricing scheme was always overpriced. (And the same goes for Evernote -- even though theirs is a slightly different offering). What should cost a couple bucks a month is priced multiples higher.
Besides, DropBox has entertained MULTIPLE exit opportunities and rejected them all.
If they disappear now, they will have only themselves to blame for not choosing any one of the multiple exits that were on the table.
The landscape changed rapidly around the early leaders. And yet, those leaders did not change their models rapidly to match the changing landscape. Knowing when to quit, and how best to exit are essential parts of management. While we may applaud unbounded grit and unshakeable tenacity -- those qualities in a CEO are more frequently disastrous than beneficial.