Thanks for reading and responding! I think the quote is true, but I wouldn't say it's a bad thing. Too many people are letting their prime years for building wealth slip through their fingers. A strategy that's safe and easy but slow is a great approach to get people to invest in themselves.
I do agree that other strategies are more powerful, and I've written about them elsewhere. I think of the four you mentioned, real estate and starting a business are the most reliable ways for most people to build wealth faster than with index funds