It was the center of learning, during the Medieval era. The idea of left (progressive) vs. right (conservative), comes from here. Student's lived on a the left bank and spoke Latin. What could be salvaged from the Dark Ages, in terms of knowledge, was sheltered around Notre Dame.

However I do not believe that this is the most 'prosperous' time. It is the opposite. Life expectancy is falling in the West. This generation will not live as long as their parents, nor be as wealth, or successful. In places like Russia life expectancy for males is just 66 years (alcohol, suicide, poverty).

Will we look back at this era, a hundred years from now, and see that from the 1980s till now as a slow steady decline, slightly buoyed by the Internet, but with most opportunities squandered.