If all you want from an investment, or a buisness partner, is a predictable return, then that's fine. However, yahoo is in an industry experiencing explosive growth and doesnt have a lot to show for it (lately).

Yahoo's history is riddled with failures to predict where things are going or failure to react correctly to when they do see. Consider that Instagram has taken off in an area Flickr has been in since before Instagram existed. The list goes on.

People are frustrated when they see a buisness that has the money and background to do great stuff and consistantly fails to deliver. There are many mature tech buisnesses that deliver profits and new product successes (IBM, Google, Intel, etc). Why invest with yahoo?

Put another way: if yahoo wants to coast on their current base, they should stop trying to expand. Otherwise they need to start seeing some ROI.