Now t he New York Times has reported RIM leadership as one of the worst in 2011, because an installed base is no longer the competitive entry barrier Michael Porter waxed about in the early 1980s.

FORBES: Drop 2011 Dogs for 2012 Stars - Sell Kodak, Sears, Nokia, RIM, HP, Sony - Buy Apple, Amazon, Google, Netflix

Purely by being so widely used, products such as Windows, with its customer base of 100m people, present a high barrier against competitors' entry.

ECONOMIST: Beleaguered Microsoft