This is not a valid breeding theory at all but a propagation technique geared to generate sales catalog pages.  It's a mistaken premise embraced by some commercial breeders hinging on the concept that any commerical sire or popular sire prospect is a valid mate for any mare whose offspring is intended for sale.  In many cases, the justification for the mating is based simply on the value or availability of the stallion season.  ("That's a $35,000 season!" or "I have a share in him and she needed to be bred.")  This mating theory is often a mistaken interpretation of the breeding adage "Breed the best to the best and hope for the best", since here, "the best" is thought to be synonymous with "the most expensive".  

This mating technique is the one most often employed by breeders with no time or interest in pedigree analysis.  It's also responsible for setting back the American breeding industry several decades in the 1970's and 1980's, and continues into the 1990's, since it promoted breeding for sales ring appeal instead of racing ability.  

A particularly disastrous variation of this "theory" was employed by many commercial breeders during the 1980's when "summer sale quality" matings were geared almost entirely to appeal to certain European, especially certain Arab buyers.  A whole generation of top-of-the-line fillies and mares were mated with the intent of producing a foal (usually sired by a Northern Dancer-line stallion) that would theoretically run well under European conditions.  The results muddled the Thoroughbred gene pool to a remarkable degree.