Re: Once again
Because any other form of economic system eventually devolves into tyranny!
Socialism, communism, fascism, etc. cannot be imposed on a populous without the direct force of government. i.e. fear of imprisonment or death!
Capitalism is an economic system operated by the people with government only regulating where it is necessary.
In controlled economies you will always see the proliferation of black markets because humans will always seek their own advantage no matter what governments do!