Nightclubs are one thing. I said "a" reason, not "the" reason. People don't go to the expense and trouble of living in cities because they have the bare essentials of keeping yourself alive. That is available in any town.

People move to the city because of things to do which includes nightclubs, restaurants, museums, theater, sports venues, cultural events, etc.

If all you want is a bunch of houses and roads connecting them and basic public services, you can get that for a fraction of the price in the suburbs.