Most countries will not legalize bitcoin as a mean of payment because the government does not want to give freedom to all its people with assets that cant be controlled like bitcoin. Centralization is an idea that benefits the government because with it the government can regulate financial and economic flows. We must have often heard that volatility is the reason why government are reluctant to legalize it as a mean of payment other than accusation that bitcoin can always help finance terrorist and other illegal transaction on the black market.

I don't know if we will reach the global adoption stage for this decentralized asset or not. But to expect wider adoption with a large number of users willing to use it as a mean of payment is always possible. However, price stability will be very difficult to achieve considering the supply and demand factors.