The Wikipedia article op is referring to can be helpful, but it's important to note that it can be outdated or misinterpret certain things, as well as assume it's legal somewhere when it's just not illegal.
In any case, I agree that the lack of adoption is not on the governments. If we're talking about democracies, laws change actively when there's a strong public demand for something. The demand for Bitcoin as a form of payment is simply not high enough to prompt major changes and adoption. It can change over time, but let's also not forget that Bitcoin blockchain doesn't scale well (I'm talking about the limit of processed transactions per minute and transaction fees when the network gets congested). The op is correct to point at the importance of scalability.
Of course, people here can say that there are alternative, off-chain solutions to address that problem, but then we lose some of that decentralization and financial freedom that came with Bitcoin.