A four-decade boom in housing and stock prices made the Baby Boomers the wealthiest generation in history, and they are 65% wealthier at retirement than the generations born before World War II. However, a new study finds that the conditions that made the Baby Boomers wealthy was one-of-a-kind, and Millennials face a steeper curve to build similar wealth. Younger generations are buying stocks and real estate at elevated prices, and for them to enjoy the same wealth, asset valuations will need to keep rising in a period beset with higher inflation and interest rates.