Because there is trading problem.
Not everyone are addicted to this.
this isn't the reason, they are not adopting it because bitcoin isn't a valide alternative for them, it does not bring any advantages over fiat, and they do not care about decentralization
and all this because they are ignorant and they do not want to learn about bitcoin, maybe they could find that they could save time and money if they use the blockchain instead of a standard fiat circuit