One thing you have to remember is that the PS3 (to my knowledge) launched in Korea before it launched in Europe. So the PS3 launched in Korea around the same time that it launched in America and Japan. Due to that, Sony likely had very low supply to allocate to the country. Just look at the pitiful hardware sales that it had at the beginning of its life in "Other," and now look.
The Wii is supply constrained, sure, but maybe only in America and a few other countries. They have plenty of stock for a huge launch in Korea which Sony likely did not. Same for the 360, although Microsoft's stock problem wasn't as bad.
It's interesting to see that Zack & Wiki and other highly acclaimed games sell well in Korea. They're not going for the casual games like the other regions are. Due to this, the Wii isn't likely to cause an expansion like it did elsewhere. The market will have to expand with more games and time. And of course, more population.
