Share your insights or perspective on the financial matter presented in the input.

Are stock index fund likely to keep being a reliable long-term investment option?
For index funds to be a poor investment, they would have to perform worse than your alternative investments.  In this case, we'll assume the alternative to be the individual stocks.  Obviously, it must be possible to pick just the winning stocks and avoid the losing stocks, raising your rate of return... however, several studies have shown that individuals are horrible at picking winners.  We let our emotions, are biases, and are suppositions get in the way.  You could literally throw a dart, but then you either win big or lose big.  Picking the fund evens that out for you, so you don't win or lose big, but just get a consistently boring (yet consistently good) return. If you have a lot of time to put into the research, and are confident in your ability to pick winning stocks, then you can do better than the index funds.  Otherwise, sticking with the index fund is probably a smart choice.