Korea's media industry benefited greatly from decades of trade protectionist policies and government subsidies. For example, movie theaters had a maximum quota

Korea's media industry benefited greatly from decades of trade protectionist policies and government subsidies. For example, movie theaters had a maximum quota of foreign movies they were allowed to show at once, meaning bigger budget and better produced foreign films wouldn't dominate the mindspace of audiences. Simultaneously media arts schools received various benefits to produce high quality people in all areas in front of and behind the camera. This high quality labor pool, in addition to (relatively) low labor costs meant that several countries also outsourced lots of production work to South Korea for decades in animation, documentary production, editing, etc. These created the conditions for Korean film makers to be able to create very high quality productions and find their own voice -- rather than being a copy of nearby Japan or China or more popular American movie sensibilities. For decades Korean films were often well considered at international film festivals with noted directors like Park Chul-soo and Kim Ki-duk making artistically challenging films. With this foundation, and a desire from the government to develop exportable media as a pillar of economic growth, it was only a matter of time before Korean writers/directors were able to produce material suitable for foreign audiences (foreign not explicitly meaning "Western"). Over time certain Korean shows and movies, particularly ones centered around historic periods with traditional themes, found ready audiences looking for high quality content that they could connect with across all Asia where shared history and cultural sensibilities still resonated. It's really only in the last few years that Korean media has started to hit Western audiences as a major consumer pool. Some of this is a result of a massive investment by Netflix (about $500m) to produce Korean language media. This gives Netflix high quality, ready-made content, with original stories and themes that differentiate their platform from others. There's not really many other countries outside of a few Western European ones that they can turn to for this type of content. Still, there's tons of Korean media that's produced for Korean audiences that will find it hard to resonate outside of Korea due to very culturally specific content and themes. If you want a great example, "Attack the Gas Station" is a great Korean movie that's almost indecipherable to audiences not familiar with Korean cultural topics and as a result will probably never see export.