Because they are not true believers in Bitcoin, they are exposed to the psychology of short-term profitability in Bitcoin holdings. As long as Bitcoin fluctuates, they will feel panic. In this way, they cannot hold Bitcoin all the time. Naturally, it cannot be profitable.
Exactly what I was thinking, bitcoin is a long-term investment at best and short-term benefits can only be taken if you are smart enough to know market analysis and have an experience trading. I think the greediness is the reason why they won't be able to make money with bitcoin.