It's pretty clear that Dropbox valued Mailbox for its potential to be something other than the standalone email app it was. And you might be right - there might well be enough talent on the Mailbox team to produce $100M+ in value - but not making a standalone email app.
If we're being ultimately generous with Dropbox then what they are doing is exactly correct - taking a team that can create a $100M+ product and reassigning them somewhere that they can fulfill that potential. But that's of scant consolation to all the people that want to continue using the email app.
If we're being ultimately generous with Dropbox then what they are doing is exactly correct - taking a team that can create a $100M+ product and reassigning them somewhere that they can fulfill that potential. But that's of scant consolation to all the people that want to continue using the email app.