Gerstner was a tough, no-nonsense guy. Just like Bartz. Both were good at streamlining operations, cutting jobs, cutting costs, improving the bottom-line etc. Had Gerstner been the CEO of Yahoo, I bet he would have screwed up too. The thing is, it's just not their forte.
Yahoo needed/needs a visionary, someone who can give it a direction, and a sense of purpose. Someone who can cull the wrong people, and put the right people in charge to realize the dream. Technology is no retail or brick and mortar business. It's no AutoCAD too.