Throughout history, when rural families fall on hard times, they packed up their things and migrated into the city looking for work. It happened in Russia before the revolution, it happened in America during the Depression, and it is happening in Canada now. But why is this? It's because cities have more job opportunities and a wider variety of them than rural towns. A person with a real estate license in the city has more potential property to deal in than an agent living in a town with a population of 200, while some jobs can only be found in a city. Here are some typical work sectors that fall under this category.
Though manufacturing firms need big open spaces in which to set up their factories, they tend to set up shop on the outskirts of cities rather than in small isolated towns. Whether the products produced are farming machinery or column protectors, is a better location for the factory because it has access to a larger consumer market and a larger workforce to work in the factory. Additionally, there's better access to transportation (i.e. road, rail, air, sea) in a city than a town, which companies need for distribution nationwide.
When stocks are traded, it's done in a large room packed full of people waving and clamoring for attention. These stocks represent the investment capitol of rich people and companies, and where do rich people and companies tend to live? In the city, where they have made their fortunes. Banks, too, need access to large numbers of people to attract deposits. In a city their counting rooms can be easily staffed by a firm and their coffers filled by other businesses who have their operations in the city.
Workforce education is a major factor in the technology sector, and the most educated people tend to congregate in cities rather than biding their time as farmhands in rural outposts. When a company designs their accounting software, they need lots of power, lots of staff, and lots of materials, which are all easily and cheaply obtained in a city.
The media business is all about reaching people. If you're writing a blog you can technically write it from anywhere, but how easy is it for you to get information? It's true of all media, TV, movies, newspapers, books: they thrive on action, and cities are where the action is.