The American Dream promises that a combination of education, hard work and good behavior can move any citizen from humble beginnings to at least reasonable success. And for many, that promise has been fulfilled. At the extreme, we have the Forbes 400, most of whom did not come from privileged backgrounds.

Recently, however, the economic rewards flowing to people with specialized talents have grown dramatically faster than those going to equally decent men and women possessing more commonplace skills. In 1982, the first year...