How Slums Can Save the Planet?

I am a big fan of Stewart Brand's book How Buildings Learn.  It is one of the few books I read in architecture school that helped me to understand just what architecture was about.  In this article by Mr. Brand, however, I am left with an empty, wretched feeling about where he is coming from.  He describes the slums around the world as some sort of hub for innovation.  The only caveat to his romantic vision comes in this paragraph:

Of course, fast-growing cities are far from an unmitigated good. They concentrate crime, pollution, disease and injustice as much as business, innovation, education and entertainment. The recent earthquake in Haiti demonstrates the danger of slum buildings. But if they are overall a net good for those who move there, it is because cities offer more than just jobs. They are transformative: in the slums, as well as the office towers and leafy suburbs, the progress is from hick to metropolitan to cosmopolitan, and with it everything the dictionary says that cosmopolitan means: multicultural, multiracial, global, worldly-wise, well travelled, experienced, unprovincial, cultivated, cultured, sophisticated, suave, urbane.

He can only manage two sentences about the dangerous and deadly realities of living in slums before he returns to this rose-colored vision.

Now, I agree with the premise that increased density is an essential remedy to some of the problems that come with population growth.  As Mr. Brand points out in his article, there are efficiencies gained in many areas through increased density.  However, slums represent the worst of what can be achieved through density, and the efficiencies gained are far outweighed by the atrocities being lived out every day by their residents and by their lack of humanity.  No doubt, there are lessons to be learned in the slums around the world, but Mr. Brand should not conflate innovation with desperation.