After that "16 years of liberation", there was a massive economic disparity actually widening between the rural population (where >95% of China lived) and the urban population who are enjoying free healthcare, education, massive salaries, modernization of infrastructure and industry etc etc etc.

Liberal historians mourn over the destruction of ancient Chinese elite artworks but that art was completely invisible to the vast majority of Chinese who were illiterate and living in squalor working their guts out. That culture belonged to the urban ultra rich or royalty of China - a tiny portion of the population.

What about the real folk arts that were eroding because rural people were starving or barely had free time?

If you want a timeline without the cultural revolution please see India. Without going through the cultural revolution, and learning from its mistakes, there is no modern China.

(For a pop culture analogy/reference see the Dark series on Netflix!)

Because it was sorely needed.