Not just Bitcoin, it should be like this for any investment unfortunately the modern day investors hurrying everything so they expect the returns in just a month or two, if it doesn't give returns they just sell and enter when the price starts rising again. With this kind of attitude they make little to nothing in profits, the investment should be done for long term goals and needed to be consistent whether investing based on DCA or buy lump sum once in a while.
FOMO is the main disease for people who are new to the world of investment, even they are only interested in instant profits and easy jobs, even though to really be able to enjoy easy money, it is not as easy as you think... what you said is very right, even many people immediately give up when they find themselves failing in doing one trade or investment, and he leaves with all his hatred for cryptocurrency...
In my opinion, the DCA method is indeed suitable to be applied, but only on coins with strong fundamentals, considering that coins or assets with strong fundamentals have a better chance for long-term future needs.