A gold rush will never happen again. I really can’t think of a situation that would suddenly make everyone rush to one place in the world. The world is so interconnected that one area may suddenly see a spike in economic activity, but people won’t move there.
The World Is Flat by Thomas Friedman covers this well. Jobs that once were reserved for people in the developed, western world can now be performed much cheaper in places like India.
People will rush to new industries and new product categories but nothing is exclusive to a single region. Unless Elon Musk takes people to Mars and lets people find something to sell on Earth, people aren’t going to rush anywhere anytime soon.