North Korea: 2012-2016

[Dayuhan]

Look, if you quote with "", quote correctly.

A correct quote would be "Western great powers".

Next, if unsure what a "Western great power" is, accept the help of an encyclopaedia, preferably one quite up-to-date.
This one might help, but other encyclopaedia exist as well, of course.

From the link provided:

There are no set or defined characteristics of a great power.

So we still have no idea whatsoever who you meant when you used the expression.

It's late and I'm not in the mood of creating another long list (about great powers acting secretly, cooperatively and not totally obviously in history).

No need to bother, because such a list would be completely irrelevant in any case. It's like suggesting that because nations have historically reversed policy in some cases, it is therefore possible to reverse another nation's policy as desired, on cue. Just because something has happened in the past doesn't mean you or anyone else can make the same thing happen again at any time of your choosing.

The idea that any combination of Western powers can make the Chinese reverse a long-standing perception of self-interest and inspire them with a sudden desire to "fix" the DPRK makes an amusing hypothesis, but it seems too dependent on the assumption of predictable and controllable reaction to have much place in the real world.