Is there going to be a hijack of the decentralized finance as privilege to Privacies and self custodian of individual funds there in the future? If what you said happens, that means the decentralized concept is ruined.
Bitcoin is Defi and ideally an alternative means of making payments without being regulated and imposing force of adoption.
Besides looking at the countries comprised of the world powers, there's no friendliness in their respective geopolitical relationships.
UK, Russia, China, Japan, USA and the rest of them are fighting Individually of who dominantes the world's economy and global infrastructures. So I doubt if they'd ever come in agreement to legally accept the system in conjunction that even the world bank would have to accept it forcefully.
Each and every countries considering to adopt bitcoin for it legal tenders is at their own right/decisions while the risk of volatilities is paramount never to force anyone in.