Because Li Shangyin lived in the late Tang Dynasty, after eight years of Anshi rebellion, the poetic style of the Tang Dynasty has changed from the vigorous style of Li Bai at that time to the direction of introspection, and the literati has also changed from helping the world to being independent, and poetry has also changed from thinking big and thinking small. Li Shangyin's poems have little splash-ink atmosphere in the early Tang Dynasty. His poems are typical of the change of poetic style in the late Tang Dynasty, so he represents the late Tang Dynasty, but other literati are in trouble.
This is my understanding ~