"In the West, there’s a tendency to approve of it as a necessary if overzealous effort to curb China’s population growth and overcome poverty. In fact, it was unnecessary and has led to a rapid aging of China’s population that may undermine the country’s economic prospects."

Let's see how this unnecessary policy, which is not visionary or far-sighted, was implemented:

"All fertile married women in their region were obliged to pee into a cup for a pregnancy test every three months; a positive result could lead to a mandatory abortion. Any couple that somehow evaded the controls risked a fine, the demolition of the family home, and forced sterilization."

In the US we like to talk about the so called "war on women" and infringing on reproductive rights and the right of a woman to do what she wants with her body. What they were doing to women in China pales in comparison to anything women in the West go through. This is a precipitously high price to pay to mitigate the toll on the environment of having more people there.

The article mentions that China even had a better method of family planning before implementing the one-child policy. It dramatically reduced the average children per family, and more importantly it was completely voluntary:

"by the early 1970s China had adopted a highly successful voluntary family planning program called “Later, Longer, Fewer.” Its slogan was “One child isn’t too few, two are just fine, three are too many.” And within about a decade it managed without coercion to reduce the average number of births per woman from six to three, a remarkable achievement. It’s rarely acknowledged that the biggest drop in Chinese fertility came not from the one-child policy, but earlier during this voluntary birth control campaign. If it had continued, China’s birth rates would have continued to drop"

Far from visionary or far-sighted, the one-child policy was disastrous for families and threatens the Chinese economy, and was completely unnecessary. The Party wanted dramatic cuts, instead of the gradual decrease that was occurring with "Later, Longer, Fewer". In spite of several high ranking Party officials warning it would be disaster, the Party pushed forward with the policy, and it took them over 35 years to walk it back.

Part of the reason they're walking back may be that, as China's economy continues developing, it is starting to cost families more to raise children, so economic forces may be forcing them to one or two children anyway:

"One survey found that of Chinese families who today have one child, 60 percent say the reasons have nothing to do with the one-child policy. The cost of educating a child is often the foremost obstacle."

Disastrous family planning didn't save Beijing from disastrous city planning. Shanghai is larger still than Beijing in terms of population, yet Beijing still has the worse solution problem. (To be fair, Shanghai still has a pollution problem, but there is little precedent in city planning at the scale of Shanghai and Beijing.)

The article paints a vastly different picture to the idea that the one-child policy was one of the most visionary and far-sighted policies of any government at any time. In fact, the evidence presented by the article says the one-child policy is almost the complete opposite of a visionary and far-sighted policy.