Sure they can, but if Yahoo really was at the point of no return, then it ultimately being sold for parts can't (in isolation) be used as an indicator of her performance. I remember when she took the helm thinking that it would take an unbelievable feat from anybody to turn that company around.
She's similar to John Chen (Blackberry) in the task they seemed to be given. Both brought on to captain a ship that was taking on water.
Instead she decided she wanted to be a newspaper/tv channel, instead of a tech company. Look at the trajectory Medium.com has taken, or wordpress, even atavist. Vox Chorus and Gawker Kinja. Instead yahoo chose to continue to compete with about.com as a crappy content mill / 2nd layer newswire.
Yahoo Fantasy and Yahoo Finance and Yahoo Messenger and Flickr were all basically left to die. There was really no reason NOT to clone FBMessenger/Line/WeChat/QQ/WhatsApp. They should have been adding features to Finance and Messenger every week.
I suggest reading the various articles that were written about her in 2015. From what I've read of her tenure, this isn't a case of an MVP who didn't have enough support. Mayer being a bad hire / performing poorly AND Yahoo being at a point of no return can certainly co-exist with one another.