The relationship among different Chaebol families is less like different Mafia factions, and more like different Wall Street bankers. They may compete in the market, but they're all in the same boat, and they have a vested shared interest in keeping themselves largely out of the law's reach.

Moreover, virtually all of them are connected to each other (and to most powerful politicians) via marriages. In a sense, they are one big (corrupt and powerful) family.