I think one of the major reasons why some traders do lose all their investments is because they enter into the cryptocurrencies market with a gambling mindest , they see the market itself as a platform where they can gamble on a coin and make profit if their predictions go right..
When a trader sees crypto trading as gambling , it will make the trader to just enter the market blindly because they are only relying on luck as the only factor which would make them to earn profits on their investments..
Having gambling mindset when trading on the market would make the trader to enter the market without any form of risk management because the trader already assumes that he or she is just gambling on the market and won't bother about risk management because they already see the platform as a place for them to gamble and make profit or loss, so because of that such person just jump into the market and waiting for luck to come before they can earn profits..