I didn't realize the extent of the IPod's dominance until seeing this WSJ article describing the demise of Sony's Walkman cassette player (at least no longer manufactured in Japan). The Walkman was itself a classic category-killer. Small radios, a staple in American culture, went by the wayside for the individualized experience of Walkman and other cassette players in the 80's and 90's. But then the coming of CD players (including Walkman's CD player) and especially Apple's IPod and its competitors meant that the days of the cassette Walkman were numbered.
Except for small fact.... the Walkman cassette is not completely dying. The manufacturing has been sold to a Chinese-based operation. Sony says it will continue to sell the product overseas especially in Asia and Middle East where tape Walkman demand is not “totally zero,…” The point is that in today's global economy, when your product cycle wanes in the core markets, there may well be a second life in other markets developing on a different cycle.
In some cases, demand for an old product put on the shelf may actually roar back because of renewed demand from a developing economy. In the automobile industry, demand for manufacturing and parts technology has been renewed due to growth in China and India. For technology providers, this sometimes means dusting off the processes and equipment for older generation parts that are still high quality and meet the immediate needs of the OEMs trying to meet end user demands.
So it seems that more traditional products shouldn't be shelved just because they've lived out their cycle in your core markets. Product managers should make more thorough checks around the globe to find the emerging pockets of demand. Hang onto those specs and blueprints.