Financial planners encourage most people to put nearly all of their portfolio into stocks when they’re younger, and to keep stocks the main focus of their portfolio for decades. This is just scary and a horribly unsafe way to invest.
The argument is something along the lines of, “The stock market earns over 8% per year over time. In the short run, it’s a little volatile, but in the long-run, it’s a fantastic investment, almost always.”
In reality, the stock market doesn’t return 8%. After the official inflation rate, it’s like 2%. After the “real” inflation rate, the stock market actually loses money over time systematically.
I wrote more about this at Stand Strong Research, my main investing and economics website. You can finish reading the depressing statistics here… note that all the data is based on the “official” inflation rate, meaning the data is the best-case scenario data.