Personal opinion, for reference only: Just two points,
1. Ancient Chinese poetry has rules. It is written according to the rules of rhythm and obliqueness. It is cadenced, catchy and difficult to write. , you have to have a good level to write, unlike modern poetry where there are no rules and anyone can write randomly, so it cannot be a square.
2. Ancient Chinese poetry has been eliminated over hundreds or thousands of years of history, and what can remain is the essence. Modern poetry has no vitality at all.