I believe the notion of "creative destruction" is considerably broader than the notion of obsolescence, at least as the term obsolescence is usually employed. I read obsolescence as implying technical decadence. Creative destruction might well occur to firm's whose product remains technically cutting edge but does not meet emerging tastes or changing factor prices. For instance, steam locomotives in the 1940s were certainly the best technically ever produced, however, their replacement by diesel electric locomotives was a consequence of escalating prices for coal. John Howard Brown