Because the father -- one of the fathers of the Industrial Revolution, Adam Smith -- was convinced that human beings were by their very natures lazy, and wouldn't do anything unless you made it worth their while, and the way you made it worth their while was by incentivizing, by giving them rewards.
Учир нь аж үйлдвэрийн хувьсгалын эцэг Адам Смит хэлэхдээ "Хүн байгалиасаа залхуу бөгөөд өөрт ашигтай гэж үзсэн зүйлээ л хийдэг. Хийх ажлыг нь ашигтай  болгохын тулд тэднийг урамшуулах шаардлагатай" гэжээ.