why people keep up their traditions and practice them for centuries?

Видимо, так легче выжить в этом мире, опираясь на опыт предыдущих поколений.

People pass the tradition of his nation from generation to generation to keep the heritage of their ancestors, to absorb their culture, not to lose the value that has been acquired over the centuries, which carefully passed down from father to son in the form of legends, myths and folk festivals. Only the person who knows the history of his nation can be truly educated.