They are invariably, actually, not very valuable at all beyond the fruition. Take a look at any Forbes or FT top 100 list and see how many of those companies are being run by founders.

Companies go through a lifecycle of change before they reach anything resembling stability or a pace of business that isn’t completely volatile the people in it. During that time the types of people that the business need to achieve the goals of that lifecycle stage are very different.

Steve Jobs types, on the other hand, are actually extremely rare and the exception rather than the rule.