I used to support our office in S. Korea. It's true they depend super heavily on ActiveX and other weird applets/software that runs only on Windows and/or IE. A lot of the communication with the government (yearly tax submission) as well as banking software would not run on our Linux or OSX devices, and so we had these 'loaner' windows 'tax machines' that got reimaged every few days that people could use to do their…
Hancom did release a Linux version of their office suite a few years ago, and regularly updates the OSX version. Moreover, Hancom has been dabbling in Linux for over 20 years. They even maintained their own Red Hat-based distro at some point. They also support OpenDocument and OOXML fairly well. In short, Hancom has been hedging their bets very thoroughly. So if the government adopts Linux by any chance, it won't be difficult for them to go fully cross-platform and keep their lucrative government contracts.