Short memory, short career or just sexist? In less than 2 years at Yahoo, Mayer brought in unprecedented leadership in a byzantine group left unmanaged for years.
Doesn't Ballmer beat her wildly in being lucky/overrated 2001 to 2011? Remember the disastrous yahoo buy out in 2008? Talk of being lucky that it failed. Or Blackberry?
Mayer turned around Yahoo's perception and fixed key products. She pointed out a talent and reputation issue and tried to solve that (http://qz.com/184046/yahoo-says-marissa-mayer-has-fixed-its-...) - should Yahoo just have done and bought nothing because of increasing valuations?
There's no actual point to ad hom like this. Yahoo's strategy is not solely Mayer's. It may not be working, you can disagree with it, it's plain populist to single out Mayer.