Pabrai examined this list and determined that if you had started with $10,000 invested in the most valuable businesses in 1987, when Fortune released its list, and every subsequent year reinvested the funds in what was at the time the most valuable business, in 2002 you'd have an annualized gain of 3.3%. During the same period, the S&P delivered about a 10% annualized return.
You can clearly see from the results that the maximum pessimism approach would yield a far more superior result. As the saying goes, what has risen shall fall, and what has fallen shall soon rise again. Surely not every stock that deteriorates will again rise -- it's up to you to provide the thorough analysis and determine whether or not a superior investment opportunity exists.