The question this article aims to answer is obvious. Unless you invest on Index Funds consistently over the next decades, you won't be able to retire early. That's a given. However, I would like to point out that since the 1900s, the average annual return is around 9% and only in the 1930s and 2000s decade the return was negative. That is, in the last 12 decades, only in two decades the average annual for the given decade the returns was not positive. So I would argue that anyone investing in Index Funds in the long term are pretty much guaranteed to make average annual return of about 9% over the course of their long term investment. This is the best anyone can do on the long run.

Read L.D. Simmons comment below and dig into why you most likely won't be able outperform professionals. Picking stocks is a game were you take on the market risk + stock selection risk + timing risk+ sentiment risk. Investing in Index Funds is taking only market risk. Why would you take additional risk in game that you are most likely going to lose in the long run? Additionally, by trading stocks and realizing a profit you have to pay taxes + trading fees for the transaction. These additional cost will eat away your profits.