There's a key aspect of mixed use that its proponents ignore. It's commonly called the pizza delivery driver problem. Think of two pizza delivery drivers. All evening long they pass each other coming and going. Why? Because which pizzeria one prefers isn't dictated by geography. Same deal with mixed use. You may live in a building that houses a hair salon and a restaurant. However, you're just as likely to use a hair salon on the other side of town as the one on the ground floor, and probably more likely to choose a restaurant that is further away (to emphasize the fact that this is a "night out"). Thus, having those amenities in your building likely doesn't change your travel habits. Also, I've not seen very many people who work in the same building they live in. It may happen from time to time, but I believe it's quite rare.