The only justifications I can think of for buying Blackberry are a: to rebuild them, b: to integrate their good tech into an existing system (a good play for an also-ran smart phone that wants more market share and is willing to gamble for Blackberry's old, loyal enterprise market), c: to deliberately put them out of business (a good play for a successful smart phone to either go after the vacuum created by their death, or prevent competitors from exercising plan B).