China also bent. But in a way that is very different from what people expected. There was this idea that economic freedom must lead to political freedom. It was the cornerstone of political calculations for a century in the west. But it turns out China bent on the economic side without bending on the political side. This wasn't preordained, if hardliners in China had won their battle against reformers China would still be trapped. But by the time that it became clear that this was the greatest miscalculation of the last half century, it was too late. China became too entrenched economically in the global order for any sanctions to be possible.
But sanctions have worked. Iran doesn't have nuclear weapons because of sanctions.
What sanctions don't do is they don't lead to regime change. But they absolutely lead to massive behavioral changes.
There are sanctions on the NK leadership and you have to convert them and their children into the Western way of thinking before they can even give open information to regular people. Right now Russia just started to censor its internet and Western values together with Western media cat still freely flow to Russia's people. This window of opportunity is closing rapidly, over though.
> Compare that to China for whom we gladly swept the Tiananman Massacre under the rug, respected their sovereignty, made them a top trading partner and they have also not bent an inch.
Because China has ~ 1B people and it heavily censors its media from the start. You cannot change mentality of so many people so fast.