Why did poetry flourish in Tang Dynasty and why was Song Dynasty a ci?

Well, I think it conforms to the law of historical development and exists as a cultural phenomenon. Song ci is a continuation of the cultural context of Tang poetry, and there must be a process from Tang poetry to Song ci. First of all, the rise of Tang poetry is mainly due to the advocacy of the monarch in the Tang Dynasty, which is based on poetry, so poetry has become a shortcut for literati to obtain official positions. Another important reason is that, based on the previous generation of Yuefu folk songs, 19 ancient poems, and the experience of poetry creation in Jian 'an, Zhengshi and Jin Dynasties, the developed Tang poems can meet the needs of people to express their feelings. However, the metrical poems in modern poetry are easy to be bound and can't be created and played freely because of its strict metrical restrictions, which is one of its defects. Where are the words? Ci rose in the late Tang and Five Dynasties and flourished in the Song Dynasty. The prosperity of Song Ci also has its specific historical background and social conditions. As far as Song Dynasty is concerned, with the development of commodity economy, the prosperity of urban handicrafts and commercial economy in Song Dynasty is the material basis for the prosperity of Song Ci. Compared with Tang poetry, the format of words is not so limited, which can better meet people's needs to express their emotions. Therefore, after the Tang Dynasty, Song Ci developed greatly, but this development was based on the economic and cultural prosperity of the Tang Dynasty. Another point is that the expansion of the civil class in Song Dynasty made Ci culture adapt to the prosperity of social economy and develop rapidly. The form of words is short, and words characterized by singing, like poems in the prosperous Tang Dynasty, have developed very prominently. I remember my teacher said that a typical example is Liu Yong, which belongs to a public class. It was from the pre-Qin period that this kind of poetic art was continuously inherited and developed by later generations. It also reflects that with the development of productive forces, people pay more and more attention to spiritual life. I hope you will be satisfied with my explanation.