Takeout and restaurants that do takeout are either easy on demand foods or complements to the core business. I used to work at a coffee/sandwich shop where catering drove margins -- delivering a box of sandwiches to a business meeting or small event is enormously profitable, but wouldn't keep the lights on.

The problem with cooking anything on demand is that scaling up distributed cooking doesn't work well while preserving quality. If you want cheap, you get fast food, and if you want expensive, you have a quality cafeteria.