How a person invests depends a lot on what time line a person is looking at before they need the money.

If they are saving for a kids college education or are 70 years old and expect to travel and spend money another ten years before slowing down those scenarios are a lot different than someone who is 30 and putting money away yearly in an IRA for retirement 35-40 years away. A person with a long time line dollar cost averaging in an index fund to the stock market is probably going to be their best bet.

But someone 75 does not have ten or twenty years for an investment to recover from a 40-60% drop, which the stock market has done in the past. Could it happen again? I think so, but I do not know.

I personally at 71 am taking some very big profits and putting it in cash. It may not be the best decision for making the most money long term (cash is almost assured of losing its purchasing power), but I'm not sure I have much "long term" left in me anyway. I still have long term investments (including farm land), but diversifying a little at my age and with the stock market pricing where it is at seems prudent.