Not all cities have lack of surrounding infrastrastructure that make it impossible to reasonably commute into the city for work. Chicago, for one, has a good r

Not all cities have lack of surrounding infrastrastructure that make it impossible to reasonably commute into the city for work. Chicago, for one, has a good rail system that reaches into a large number of surrounding areas (about 40 - 60 miles out), and also has decent roads that take between 30 - 45 minutes to commute in from a number of areas. And a lot of jobs here are "close" to the city, but not in it (due to land for large campuses being cheaper).