Imagine a startup that generates a $billion in profit from factory made gadgets, but reinvests the profit in bad ideas poorly implemented by office non-workers, effectively middle-class welfare jobs program.
Koreans have a strong sense of community, and are extremely group-oriented. Sharing, fairness within the group, and conformity to social norms are highly valued.
As a side effect, when a product becomes commercially successful, a large bureaucracy is quickly established underneath it, which subsidizes a lot of other unproductive activity and becomes dead wood over time.
I don't see any point in arguing about secondhand anecdotal data about working conditions at one specific company (I could regale you with a dozen such anecdotes heard from friends about working conditions at American companies), but South Korea's HDI is now 0.891, above countries like Japan, France, Austria, Belgium, Finland, Italy, and Spain: http://en.wikipedia.org/wiki/List_of_countries_by_Human_Deve...
For comparison, Japan has 1735 hours, US has 1788, and Germany has 1388 hours.
As for the "success", well, somehow South Korea has experienced near-miraculous economic development during the 70s. Unfortunately, somehow we forgot to understand that economic development is a means of attaining better life: it became an end in itself. We can still find lots of people saying "Vacation? What vacation? How can we become a developed country (like the US or Japan) when we get all the same vacation as they do?"
Argh.
Edit: For extra craziness, replace "vacation" by "weekend". (Not unheard of.)
To me it sounds like a recipe for a miserable work life. The Japanese/Korean schooling systems are very tough and strict compared to other wealthy countries. Maybe this is why they became so wealthy? Also, this statistic claims to not be based on economic output, but it basically is. And in order get the highest economic output, that is going to require really hard work and a lot of rich people/companies/countries investing in you. Of course some countries have unfair advantages and don't need to work so hard.