Even though I'm picking up Martin Geddes again, I don't think any apology is needed, because he does have a habit of raising some interesting questions about business, creating good opportunities for systems thinking.
In his latest blog posting Divergence at Tesco, he notes that Tesco is reducing the range of mobile phones on offer in his local store, and has no 3G phones at all. He interprets this as a sign of a weak market for mobile phones in general and 3G in particular. (Obviously there are some other possible interpretations. And we certainly cannot predict the collapse of an industry from a single observation in a single store.)
Martin rates Tesco's strategic nous above that of the mobile phone industry ("Tesco, as one of the world’s most astute and profitable retailers, generally gets these things right.") But in the grocery market, if the major supermarkets decide not to stock your product, you're dead. This makes Tesco's anticipation of low market demand self-fulfilling, at least to some extent. And Tesco is accustomed to dealing with manufacturers that will do anything for shelf-space, including humiliating discounts. (In this context, viability entails being nice to Tesco at all costs.) Clearly the phone manufacturers are not that desperate. Yet.
Martin has had doubts about the viability of the phone market for a long time before he made this observation in Tesco. So this observation simply corroborates his previous hypothesis, and we don't need to challenge his reasoning in this particular case. But this small observation raises a more general question: what can retail shelf-space tell us about the viability of an industry? And if we wanted to use this as a rough metric, what other information would we need to cross-check it against?