I think the reasoning must go one step further -- project managers and _especially_ executives need to have rich personal experience with building software. Th

I think the reasoning must go one step further -- project managers and _especially_ executives need to have rich personal experience with building software. That doesn't necessarily mean that they must have spent years programming for themselves, but at the very least they should have spent a few years closely paying attention to the whole life-cycle of software projects. That way, they can appreciate the difficulties of estimating delivery timelines for an evolving scope, the nasty surprises that will invariably bite them in the ass, what technical debt means, the value of refactoring and consolidating, how something that sounds simple can be hard and the canaries that indicate a certain feature has that property, and so on. The most formidable product person I know has spent six years working closely with a team of five engineers, on a portfolio of complex products. He can often predict technical challenges before the engineers see them. He's the best tech executive we dream of in our organization, but due to the diseased nature of executive hiring at our firm, it's not very likely he'll get a job at the top.