Up the Beanstalk - Put A Second Story on Earth?

Reading 'Cradle to Cradle' (highly recommended bestseller by M Braungart & WMcDonough)  and their section on the role of Ants in making the world a better place reminds one that without a living eco-system how can the Bees and Butterflies and Ants do their jobs of keeping living things in production, how can Beetles do their clean up jobs, how can Ants eat dead things, and do their job of growing important fungi, how can Worms till the soil, feed the Birds, who are also pollinators, and seed distributors?  These vital little critters need soil, gardens to do all of this.  This hearkens one to the question : why are the proponents of the Outdoor Room so keen to downsize nature in our already built up cities?  I think if they had their way they would build a second floor on to earth, and construct a fake bean stalk to get us there.