I understand that some critical mass is required for a city to be diverse, but why do we keep adding people to megacities? What's going to happen after people oil, when the world starts running out of resources. Shouldn't we take ethical, but preemptive action to reverse the growth in our largest cities? Why do we need megacities to grow to 50 million? Couldn't 500 000 provide all those things you mentioned, or do we everything copied and pasted a thousand times over?
A city of 500 000 could provide you with all the amenities you need. You could have an airport, university, ethnic restaurants, yoga classes, and specialty shops. Ok so maybe will give up 100 story high sky scrapers, and the largest sport stadiums. Is it worth driving 3 hours in traffic, just to have a few skyscrapers?
Escaping the city to find adequate nature isn't a walk in the park. You have to drive almost 150 kilometers from Toronto, just to find a large piece of forest. Everything to the south has been heavily fragmented for farming and urban development. We are becoming extremely alienated from nature. We work 9 to 5, 50 out of 52 weeks of the year, just to get by. Most kids today, don't know what it's like to live with the land. They are trapped in the concrete jungle all their life.
Here's a photo of a traffic jam in China. Why would the rest of the world want to catch up?
Our ancestors use to appreciate the land that surrounds them.
Let's contrast that to a Ghetto in Bogota, Columbia. Over-urbanization sucks.
I think one reason is the the rich want to find a city they want to own. Countries like the US have a number of large or mega cities. But for smaller european countries, there is one megacity for each country, usually the political and financial capital is also the same in such cases e.g london in uk, paris in france. And most megacities will be close to sea or have a port near them.
Historically if you see, the rich people were the merchants who did global trade. They settled close to sea ports and most of the rich network built around those cities. Then as we moved to mordern times, more people started moving to these cities because of better employment opportunities. And people keep moving there because the rich never move. They keep occupying a small section of the city, for example manhattam in new york. Moreover, having an office in these areas, where real estate has gone through the roof is not only a status symbol but also the place is ripe for business.