First of all, from the historical environment: the Tang and Song Dynasties were open, and poets were bold and unrestrained, while poetry could express the author's feelings and show the author's literary talent; In fact, there is also a Yuanqu. Why was it popular in Yuan Dynasty? Because the Yuan Dynasty had very strict control over the Han people, which of course included culture. So how should these talented people write their feelings? This kind of folk art drama can only be used to insinuate the contemporary court and society. Novels in Ming and Qing Dynasties were also created under similar circumstances. Anyone who has read the four classic novels knows that they all show dissatisfaction, resistance and ridicule to the present society.
Secondly, from the perspective of literary development, it is not difficult to find that ancient Chinese is difficult to understand after careful comparison. It may take you most time to translate Li Sao, but it is relatively easy for you to understand a poem. By the same token, in the past, perhaps these poems could only belong to intellectuals, but with the development of the times and the popularization of culture, these elegant things have also spread to the common people, so popular literature has become more and more popular and vernacular culture can be understood by everyone. Just like now, we no longer use classical Chinese, but use vernacular Chinese, so that people who know words can understand it.