The reason is simple. Many governments are not aimed at improving the welfare of their citizens and therefore prohibit bitcoin. Or they are afraid for their national currencies, that they can not withstand competition with bitcoin.
Yes they know about the power of bitcoin, they have noticed the increasing interest of people for bitcoin, to me it is not possible to lose profit and my interest for bitcoin so I can feel that other people are also dreaming the same, I know bitcoin has very high potential to increase in price, but we will have to keep patience soon same as Japan and South Korea our government will know how good bitcoin is for the economy of the country, so they will accept the presence of bitcoin with open heart and open arm.