Chapter 16&17 Curiosities

I'm not sure how economically free communist countries are but I can make a fair assumption that they are generally less free and open when it comes to trade. This makes me wonder that if trade equals wealth and if the more economically free a country is the higher the GDP per capita, why doesn't countries like North Korea, Afghanistan, Myanmar, and such give up a little bit of their authoritarian regime in order to make the country more economically wealthy? I know it would depend from country to country and from leader to leader but it seems like it is both an economic and ego issue. Maybe they care more about power than stability?