I don't agree. In lots of cities you see residential/mixed use buildings in the middle of the commercial district. Look at The Austonian in Austin, Trump in Toronto, Shangri La in Vancouver, Telus Sky in Calgary, L'Avenue in Montreal, and many others examples. For instance, the Austonian is by far the tallest building in Austin, and is 100% residential right in the heart of the CBD.
http://wallytingley.com/