How powerful are chaebols in Korea?

Could you elaborate on the influence and power wielded by chaebols in Korea? How significant are they in shaping the country's economy and political landscape? To what extent do they control key industries and markets? And how does this impact the lives of ordinary Koreans? Could you provide some examples or case studies to illustrate their influence? Furthermore, how does the government regulate or respond to the actions of these powerful conglomerates? Is there any effort to balance their influence or mitigate any potential negative effects?