For one year, this man is eating only what's grown at Dubai's Sustainable City
https://edition.cnn.com/2021/01/20/middleeast/dubai-sustainable-city-food-experiment-spc-intl/index.html
Urban farming is effective where plants cannot grow, due to lack of rainfall.
Otherwise, urban farming won't be compatitive against ordinary farming, because it costs more to prepare for urban farming than ordinary farming. For example, lights, buildings, and land acquisition.
It will be important for urban farming promoters to think about how to reduce costs.
