"Product developers, brought in to witness the struggles of average consumers, were astounded by the havoc they created."According to this Reuters story, half of product returns are due not to functional defects, but to consumers' inability to figure out how to operate them. Furthermore, the average US consumer is willing to spend 20 minutes learning to use a product, after which he will give up.
I have a quibble with the conclusion of the scientist who led the study. He concluded that poor product definition was the root cause of these usability problems. I contend that the lack of usability metrics (requirements) is more specifically the primary cause. The first step is simply for companies to define the maximum amount of time and effort it should take for a typical new user to get the product working - and develop tests to ensure the products meet these requirements.