This month marks the 20th anniversary of its demolition.
Sounds to me like it did not work.
It did work, read the diagram. Just because they decided to do something else with it doesn't mean it didn't "work" it was a completely functioning city of anarchy.
But it did not last, which I would consider to be a pretty vital aspect of 'it working'. It didn't last, therefore it didn't
really work.
I'm sure if you look into it you can find remnants of that same society somewhere in the world. Where did they all go?
Actually, most of those who grew up in the Walled City stayed in Hong Kong, and the ethos infected the remainder of the middle and lower classes across the city. That is one of the contributing factors that makes Hong Kong the capitalist light that has largely led (nominally communist) China out of the darkness. China would not be the industrial powerhouse without the established culture of Hong Kong to draw upon, and Hong Kong would not have been the same without the Walled City within; and I mean that in both a good and bad way. Bear in mind that once upon a time, the communist leadership in China believed that they could teach rice farmers to refine iron and make alloy steel in grass fired clay kilns across the countryside; and
that was how they were going to be able to keep those evil capitalist American navies out of their business.