I don't think you understand how much the Alibaba shares that Yahoo held were worth (~$40 billion) and how little the rest of the business was worth (<$5 billion). This is not a normal situation, where your point would usually be correct. She had zero responsibility for running Alibaba. She ran a business that was worth less than $5 billion, but was compensated based on a stock price that primarily moved based on the run-up in the $40 billion worth of Alibaba stock Yahoo held (and such stock was acquired before she became CEO).
Here's one of many Matt Levine pieces that explained the Yahoo/Alibaba situation, although it's now dated: https://www.bloomberg.com/view/articles/2015-01-28/yahoo-wou...