The theory of disruption is meant to be predictive. On March 10, 2000, Christensen [author of The Innovator’s Dilemma] launched a $3.8-million Disruptive Growth Fund, which he managed with Neil Eisner, a broker in St. Louis. Christensen drew on his theory to select stocks. Less than a year later, the fund was quietly liquidated: during a stretch of time when the Nasdaq lost fifty per cent...