There are a couple of threads here that argue Marissa Mayer was the problem. I don't think that can be true.

Mayer took the reins at Yahoo in 2012.

Facebook had crushed Flickr in desktop-shared photos by 2009 or so, and over 2010-2012 or so, Instagram had created a whole new photo experience for mobile that Flickr missed. Instagram was acquired by Facebook for a billion dollars in 2012.

Mayer may or may not have exacerbated problems with Flickr. I don't actually know. But there's no way she was the precipitating factor.

Some of the posters blaming her are linking to articles that don't even mention her. The article just happens to use a photo of Mayer because she was the CEO at the time Flickr was sold to SmugMug.