The long commute for those who can't afford the center is not actually a law of nature. Better infrastructure gives better results.

For example, you can get to midtown manhattan in half an hour on NJTransit from East Orange, NJ, a very cheap place to live. The NYC metro area is chock full of affordable neighborhoods where the tradeoff is merely having a commute, not a LOOONG commute.

Ideally, you have your infrastructure scale as the city grows, to maintain constant commute times for workers even as they move further out.