As the article points out, Yahoo's problems began long before her tenure and Bartz's primary experience was running a company which was a market leader and was committed to making hard choices in a timely manner [Autodesk]. Nothing could be further from Yahoo's status at the time she took over - Yahoo has not been the leader in their segment for at least the better part of a decade. They are essentially the AOL of the internet - a service targeted at the less sophisticated intern users or those willing to go with their ISP's default in the case of ATT.
There's no fixing it because there is no love for the brand. People have Yahoo email addresses for the same reason they have Hotmail - they got their free email account before Gmail was available and it is too much trouble to change it.
Bartz's hiring was a classic case of drafting a CEO based on who is available rather than fit - there was virtually no overlap between Autodesk's business model and operations and Yahoo's. Hopefully, she will find a much better circumstance in her next role.