That is why the trader when cryptocurency falls usually fix the profit in USDT when it grows they again buy cryptocurrency. It is possible to make money even if cryptocurrency falls.
At the time of the collapse of the market, traders may have deposits not in dollars, but in promising coins. And then they fall into the trap of a fallen market. They have to wait for price increases in order not to lose deposits.
You are talking about investors. In any case, investors fall into such a trap. In the cryptomarket, I became such an investor

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Most likely, more than half of the traders have become investors. Since not everyone managed to translate all their deposits into dollars. Many traders waited for the market to collapse only at the end of the year.