Well some people just dont have a choice. They might have bills to pay and other needs, HODLing is just not an option for them
That is the reason experts always advice you should invest only spare money in high volatile products because sometime we may need to wait for quite long time to see profits in these investments. If you invest money which you need it immediately then your forced to sell at a lower price if prices go down after your investment.
Yes, for a market that is highly volatile, this is something that would always happen once in a while and we cannot do anything about it. It helps emotionally and psychologically when you invest what you can afford to lose and that makes you to hold on to dear life no matter what is happening to the market since in the long run, it is the future that counts anyway and not just what is happening presently.
Past history may be for reference, but like you said, the market is unpredictable and we cannot always use the past to judge the present.