There are few laboratory tests in any environment that so clearly measure the differences in political systems as did North and South Korea. Divided after complete devastation during WW II, the North took a Maoist and Stalinist central planning model and the South a capitalist American model. The results have been so dramatic that if this were a medical study it would have been called off for ethical reasons.
The South has prospered and become one of the wealthier nations in the world whereas the North has gotten to the point where most of the 24 million people who live there are starving and would die without massive food aid. Over the next few years succession issues should affect North Korea. Kim Jong-Un heir is a thirty one year old boy, who has been educated in the west. Whether he has any real power or whether he will move North Korea to a capitalist democratic model is unknown. Indeed, it is even unknown whether North Korea's leaders will move towards war with the south which many consider a real possibility.
As far as stamps are concerned, North Korea has been a prolific issuer. Philatelists are always looking for the next China-a country whose stamps had been plentiful and where internal economic success leads to a huge increase in stamp collecting and great financial gain to the early holders of those stamps. India has conformed to such a model with its stamps rising smartly. But North Korea will not join this list. It's economy is not small-it is minuscule. The people are not poor-they are destitute. Add poorly educated to the list and it would take decades of rapid economic growth to even move North Korea to the levels of a developing country. So save your money. If North Korean stamps ever begin to increase in price you will have a long warning period in which to buy them.