Everyone is not a designer
He wasn't really saying that from what I remember.
He was saying that people should specialise in what they are good at but also be knowledgable about the other areas. Which he called "T" I think. So his stance is that developers should know design put specialise in development, designers know development but specialise in design. Add in lawyers should know development and design, and likewise the designers and developers should understand the lawyers practices but let the lawyers do their job as they are the specialist in their areas.
Paul.