Doesn't your linked article counter that argument? Both the head of Samsung and a former president of SK received prison time for bribery. That seems big. I'm not knowledgeable about the full scope of the corruption, but based on that article it sounds like "effective measures" are entirely possible.
He served 200 days in jail, and seems to have lost minimal social standing. This was also highly exceptional to see any consequences at all. You’re right that the public outrage at the time was not entirely ineffective but the punishment was extraordinarily small.
