Blackstone Inc.’s private equity fund for wealthy individuals is a harbinger of two trends that many expect will transform investment management in the next decade. The first is getting a class of investors called “mini-millionaires” or “suburban millionaires” into alternative investments, and the second is pushing private equity for retail investors.

A century ago, “millionaire” meant “rich.” With mansions selling for $50,000, yachts for $10,000, servants paid $500 a year and Harvard University charging $200 per year for tuition, someone with a million dollars could live very well. Today that entire first million won’t get a mansion, or even a single-family home in some neighborhoods. It could take $50 million or so to put you in the category of a 1923 millionaire.