"collapsed under its own weight"?
Yep. You got it right. The Norks greatly underestimated the dangers, complexity and difficulty of pushing a nuclear program as Little Kim was doing and keeping all the ducks in order, and Trump simply gave him the impetus to keep pushing his program until cracks developed into fissures and a major disaster of its own brought in down upon itself. Anyone with a brain could see it coming. This guy was bound to sooner or later shoot his own foot off. This guy was shooting rockets over Japan and everywhere just daring some eventual calamity to happen! My only regret is that he didn't bring one down on his own head. I'd now give real thought to the UN sending him a bill for the billions of dollars he cost us and other countries wasted in preparing for his nonsense! Donald Trump, once again winning another war without having ever even needing to fire a shot!
The flaw in that reasoning is that every other POTUS between the Korean War and the present, put the same pressure on the North, so Rump's posturing was simply continuing what his predecessors did. So nothing changed in that.
None of those previous POTUSes however were in office when NK blew up its own facility, and a mountain with it, which directly threatened its nearest neighbor and closest ally (and its lifeline) in a way that cannot be ignored. China's status as NK's lifeline, without which it literally couldn't exist, gives it enormous power in deciding whether it will indeed continue to exist. As far as the Dim Dung regime is concerned, China is Mommy. Whelp, Mommy has now decided she's had the fuck enough.
Obviously Dim Dong got himself into that by recklessly blowing up Mantap. Now you could argue (free tip here) that Rump's Nixonian "Madman Theory" incited NK to accelerate its nuke juke, causing Dim Dung to try to do too much too fast, resulting in mountaincide (hee hee mountaincide I kill me). But not only would that be a stretch in the blatantly partisan quest to attach a personal causation to a random event, there would be no way for Rump to guarantee that result, which absent such an operational catastrophe could have ended very VERY badly, so if you want to go out on that limb you also have to bring its baggage with it, which is that it would be an immeasurably reckless gamble to play using the world's population as poker chips.
China had already denied nuke technology to its dependent 'child' since Truman threatened NK with being on the receiving end of same in 1950 --- part of the reason Truman is one of the four worst POTUSes since 1900 --- but NK went shopping elsewhere and by at least fifteen years ago was dabbling in real nukes, regardless of China's "Mommy Says No". In other words this could have gone down, say, five years ago, and it would have been equally specious to claim "Obama did it with his teleprompter".
Hate to break it to the world but sometimes things happen out there between other parties that this navel-gazing nation had nothing to do with. So if there's a question of "who to thank", the best answer seems to be "our lucky stars". With a supporting role by China, which to be fair should have pulled the plug on the wacko regime decades ago.