Inefficient Cities as Sources of New Work

As I continue with "The Economy of Cities" there have been a number of assertions that seemed relatively uncontroversial (what with my vast knowledge of development economics). However, there's no data in this book, that I've yet seen.

I've gotten to the point in the book where the author is contending that inefficient cities--those that are somewhat "organic" in their physical and economic layouts--are engines of innovation. The idea seems pretty reasonable: a number of small firms duplicating work (economically inefficient) and/or being lumped hurly-burly next-door to different pursuits, whether business, residential, or commercial (physically inefficient) may lead to new ways of doing work, new firms making new things, what have you.