The problem with cities is that what makes cities important aren't cities themselves. People don't migrate to cities because of the cities, they migrate to cities because they're looking for jobs. Cities have to deal with a political, social, and economic force, that they don't control themselves. Job market and job laws are created and managed on a national level, but their effects are local, on city level.
In premodern cities a big chunk of the inhabitants were small merchants and business owners, few were employed because you needed personal trust to employ or be employed, since there were no labor laws (or very little). Then the nation-state and the welfare state created job laws that allowed a big chunk of the population to be employed by a few companies. This reflects in the city's geography because the large majority of inhabitants today are employees. Cities today are different from traditional cities. The importance of commuting is much bigger.