What advantage did cities have for businesses and industrialists?

One could write a book about that. The most obvious item is that a city has a lot of people in one place.

Some industries can't do their business in a city so they require a mobile work force. That is why industrialists lobbied governments to build roads at public expense so their workers could travel to where their services were needed. That alone clobbered the extended family. It used to be normal for a child to grow up surrounded by aunts, uncles and cousins, but now a child is lucky to visit grandparents once a year.