One of the curious things about what Jake Weisberg aptly calls the "Do Dim Bulbs Make Good Presidents?" question is that it's not a question anyone would ask about corporate CEOs. On the contrary, it's conventional today to hear that having a really smart CEO is necessary to compete successfully, especially in the New Economy, and articles about company heads routinely include lines like "He was the smartest guy I'd ever met." You would be very hard-pressed to find someone who could argue with a straight face, pace Richard Brookhiser on George W. Bush's future prospects, that it's precisely because Jack Welch isn't that smart that he's done such a good job at GE.
It is true, of course, that the landscape of CEOs is dotted with high-profile figures who never made it through college, including Michael Dell, Bill Gates, and Steve Jobs. But the basic assumption about these guys is not that they got tired of wrestling with Introductory Calculus and quit, but that they were too smart to waste their time in school. (A debatable assumption, to be sure, but then I finished college, so I would say that.) The success of Gates, Dell, et al., in fact, is antithetical to Bush's educational career, which looks like nothing more than a rote exercise in credentialism.
The only reason this comparison really matters, incidentally, is that the same crowd that has leapt to Bush's defense has often been fond of saying in the past that we should look to business as a model for the way we run government. This was never as congenial an analogy to Republican ideology as Republicans thought it was--most corporations borrow significant amounts of money and take their time paying it back, and most invest heavily in the future, rather than giving money back to their shareholders--but an important part of it was the idea that a president needs the same skills as a CEO. (Ross Perot, too, was fond of this analogy, since he was a CEO.)
If a president needs the same skills as a CEO, then, George W. is out of luck. Actually, he probably would have fit in pretty well with the corporate chieftains of the late 1950s and early 1960s, when there was no foreign and not much domestic competition and the old-boy network was in full effect. But not-smartness doesn't count for much anymore, at least not in the business world.