I am not 100% sure if its correct but from what i heard its pretty hard to penetrate Korea market, the homologation, you also need a local partner to sell (a problem for Tesla model), again these are all soft barrier not official ones, also i think a vehicle must qualify for the EV incentives, i remember BMW boasted about getting i3 qualified due to investments and R&D in Korea, Renault Nissan have a stake in Samsung Motors.
So i may be wrong but things are much more tricky then just opening a store in Seoul and selling 100 cars a month, Tesla would have entered the market long time ago otherwise, they now even open a store in Finland