I suspect East Germany had similar reunification concepts in their day. History proved different, thank goodness.

I honestly believe North Korea isn't far from collapse. Millions of people are starving, and an estimated 2 million have already died. They have very little in the way of an economy other than weapons sales, and even that is being constrained. The real concern is whether the collapse will be peaceful or if the government will lash out in a death spasm.

Reunification between East and West Germany has proven difficult. Most of the industrial capacity of East Germany was so substandard that it had to be closed. The country was an environmental mess, and decades under communism had left the people with a weak work ethic ("They pretend to pay me and I pretend to work.") Germany has spend tens of billions trying to build up the East. It has been so challenging that some former East Germans have asked for the Berlin Wall to be rebuilt.

Once North Korea collapses, the South will have a monumental job helping bring the North into the 21st century. Decades of brainwashing will be hard to overcome, their factories are probably just as outdated as East Germany's were (probably even worse due to their long isolation). I don't know about their work ethic. I watched a news segment on North Korea that was plain wierd. Among other things, it showed a young uniformed woman in their capital smartly directing traffic with robotic precision. Only thing is, there was no traffic. The roads were completely empty.