"How did people lose their retirement investments in 2008..following typical investment strategies?" Well, you can follow those strategies until fear takes over. I know of a graduate scholar that got scared, got her money out when you saw how her investment accounts went downwards. You keep the cash, fearing that if you invest again you will loose all. You see how the market goes up, but you do not believe on it again. Or the sunk cost fallacy...or risk aversion with an overestimation of risk.

The more financial AND emotional intelligence you have the less likely you are to fall into such life.

But let's have empathy because the majority of people have less financial intelligence and cold blod as the average hn reader. Let alone the chance of earning a very good salary for a few decades.