She took over Yahoo on July 16th, 2012 when Yahoo's stock price was ~$16. It's now trading at ~$48. That's about a 3x.
Google over the same time period has done about a 2.8x.
Microsoft over the same time period has done about a 2x.
There are 100 HUGE reasons BESIDES Marissa that we can account for their shareholder success eg (1) they were trading at a lower PE than market competitors (2) they had a huge Alibaba share that was worth more than the entire Yahoo company when she took over (3) MSFT offered ~$45b in 2008 which means their ~$46b current enterprise value is a huge 9 year failure!
BUT I think that Marissa played the critical role of "responsible adult" that gave the market a reason to let Yahoo survive as an independent.
She had a huge brand name that she lent to Yahoo, and each of the 3 reasons I list above were to the board's detriment.
If anybody should get the fuck you it should be the Yahoo leadership of the mid-2000s, and the board's leadership since then.