The main reason why most trader fail in trading is that they are not trained in the craft, most experience traders as they call their self don't even know how to identify the least support and resistance, talkless of knowing how to react when they see some certain chart pattern or candle stick pattern.
The skills I believe that are required to come out profitable in trading are;
* Knowledge: know the craft, know what you are doing, don't trade on assumption.
* Know how to control your emotions: it's very important that you know how to control your emotions like fear and greed in trading.
* Know how to manage your risk: knowledge and emotional control gives you money, but proper risk management skill protect your money and your gains
most mistakes of traders are;
* Thinking it's a get rich quick scheme or thinking that it's easy.
* Having no proper training in the craft to attain knowledge about it.
* Watching one two or three video's on YouTube by one YouTube influencer and think they are ready for it or thinking they have known the craft.
* Having no experience traders that is good in the craft to guide them.
Maybe the only thing I can add to what you said is that they were just told, hyped, or promised. It could also be because they watched it on YouTube and were enticed to enter crypto trading, so they are here.
It is also possible that others are exploring themselves to see if they can see an opportunity here in cryptocurrency. So there are many reasons why they fail, apart from greediness, and the ones you mentioned above.
And most of the time hypes is the reason why trader start gaining interest they might see it from a friends or relatives who venturing to this venue and they think that it will be easy for them duplicating the outcome, but it turned out that because of lack of knowledge they ended up losing their money, its important that you have the right sets of skills and knowledge before stepping into this business,
Trading is a never ending learning process even how good you are there's no assurance that you'll be able to keep the positive streaks but the chances to avoid or prevent losing a lot, you can work on it by using your skills and experience.