Product differentiation has been widely regarded as one way for
firms to isolate themselves from the pressure of competitors and
thus obtain superior performance (Bain, 1956; Dickson & Ginter,
1987; Porter, 1980). Defining long ago this critical concept in firm
strategy, prominent economist Edward Chamberlin noted that “A
general class of product is differentiated if any significant basis exists
for distinguishing the goods of one seller from those of another and
leads to a preference for one variety of the product over another”
(Chamberlin, 1933: 56).