Lou Gerstner and Meg Whitman are two examples from the technology world. Both came into their jobs at IBM and eBay with zero tech experience, but got up to speed very quickly. Of course, had they failed to do so they would have been out within a year or two.
Amazon has continued to grow in simplicity and coverage, including ease of purchase with third-parties (eBay's dealer market). Meanwhile, buying on eBay is still a huge pain, with no integration between eBay and its own subsidiary.
And this is the real truth of the matter. The above posters are correct, you do need knowledge of something to run it, but understand that business knowledge and experience is ALSO that "something".
Once you obtain certain scale, you can't do everything. It's equally ignorant to think an engineer can run a business top to bottom as it is to think an MBA can fully run an engineering company.
I so often read here MBA used pejoratively, but remember that most small businesses fail because they're run by people who have skills but no idea how to run a business. A major corporation needs both (and more!) skills.
Exactly.
A few years back, I found myself in a one-on-one saying: "you would think someone taking a job managing a hog farm would at least know what a hog is."
Though, that was about web-development.
A suitable allegory.