Money and Power
"Korean courts are not keen on locking up big business bosses, who are seen as a vital and central part of Korean society."
Sadly most countries will react the same way. Money and Power are very closely linked. So he gets just a suspended sentence, when most normal people would be inside if they tried to take 1% of what he has tried to do.
Money and Power are always linked. Its in the best interests for big businesses to have friends in government, because then they get better deals, government help and government concessions in the future and it helps government members to have friends in big business, because once their job in government comes to an end they get the big jobs in big business. Plus this helps the businesses have political contacts in their companies with friends still in politics.
... "Its not what you know, its who you know", as they say.
Big business often treats the law more like formula one rules. Big businesses look for ways around a law, and then the government says things like, e.g. “ok so if you get around this law now, we will clamp down in this other area later hurting you more, so don't get around this law now”. In high power circles, its all political chess moves, rather than uncrossable absolute laws. Laws are only absolute if you have no power. If you have lots of money and so power, sadly the law is a lot more flexible.
But then corruption provides a competitive business advantage (and political advantage), so its sadly no wonder it continues to exist.