I think when the Fiat ecosystem was introduced, many people rejected and did not believe in fiat. You can imagine, gold was replaced with paper, it looks like nonsense. But after a long journey, everyone now believes in fiat and it has been adopted en masse. It's the same with bitcoin, fiat is paper that can be seen and touched whereas bitcoin is digital money that can only be seen on digital devices, that sounds like crap too. So just wait for bitcoin to become a new financial ecosystem, and bitcoin needs "time" to get there
Fiat is a centralized currency that is completely government controlled - while governments cannot control bitcoin although they can introduce regulations for their users. The main barrier to mass adoption for bitcoin is government regulation - that is an undeniable fact.
You cannot expect all the world's governments to agree to adopt bitcoin until it reaches the level of adoption of fiat as legal tender. I hope that bitcoin is adopted as an alternative option that will not replace fiat as the main currency. While you can hope the passage of time - you can get governments to adjust their regulations on bitcoin, but I don't expect governments to fully agree to mass adoption of bitcoin.