Why China's traditional Chinese paintings are mostly freehand brushwork, while westerners' western oil paintings are not freehand brushwork?

Chinese painting pays attention to the interest of pen and ink, and the pictures range from layout management to inscriptions. For example, there are only a few strokes of freehand brushwork, but it contains the knowledge of composition, brushwork and the use of ink color. The freehand brushwork of Chinese painting pursues significance. Western oil painting is the relationship between light and shadow, and it is a three-dimensional expression. Oil paintings give people the feeling of photos, while western oil paintings pay attention to modeling.