[mathattack]

This highlights the problems of strategic thinking in general. You can always miss something, which is why strategy should be taken with a grain of salt. It's also why some of the great strategists fail as managers of their own firm. (Look at Monitor, founded by some of Clayton's colleagues at HBS)

All that said, I'm still glad that he went out on a limb, and that he was able to fess up to the mistake. Very few business or econ professors are willing to do either.