So it increasingly looks like the inter-Korean Kaesong industrial zone is closed for good. (The Wikipedia write-up is a pretty good quick history of it.)
The zone was set-up during the Sunshine Policy period (1998-2007). It was to do 3 things: 1) Lead to some liberal-capitalist spill-over in the North, 2) Expose regular North Koreans (the workers in the area) to regular South Koreans (the managers and staff), and 3) Generally provide some inter-Korean cooperation that might hopefully reduce larger tensions. A resort area in North Korea (Mt. Kumgang) was also opened along these lines in the Sunshine period. Broadly the idea was along the lines of liberal explanations for the Soviet Union’s changes in the 1980s: the Helsinki Accords and CSCE opened the USSR to the outside world, and the inflowing liberalism slowly changed attitudes that eventually helped wind-down the Cold War. Unfortunately, none of this seems to working in the NK case.