If you diversify enough, you can ensure a 0% return and a 0% loss. The argument for "diversification" is a recipe for safety, but not real wealth creation. Real wealth creation isn't "sticking your money in an index fund." It's a very middle class approach but as with anything, there's no such thing as a free lunch. If it takes 30 years of index funds to be able to retire, then you're doing it wrong. Investing in actual cash-flow producing assets is how you create wealth. Capital appreciation is only one part, the other part is creating cash flow. That means owning businesses, real estate and other passive income generators (IP, for example.)