Dude — that is a low blow. First off, Obama did inherit a crappy economy — one that was spinning out of control. And also had to handle two wars draining the US coffers. Why is that a “successful tactic”?
As for Marissa, with an organization as large as she inherited and the overhang that was there — my guess is that it was already a challenge. Turning around that big of an organization with little in the way of specific business opportunities (like IBM had when it shed its hardware businesses), Yahoo! has always been about innovation and the irreverence that made Yahoo! Yahoo!. Marissa has always been a product person — and expanding that role may have been costly in some ways since she was also required to keep the culture alive, keep the teams going and expand the business.
With an organization that even the founder (Jerry) did not manage to a level of success that Wall Street would appreciate, I am not surprised that Marissa had many challenges. While I am certain she is no perfect manager, I am of the belief that she worked to deliver for shareholders and the company.