So...Kim gets the legitimization and the seat at the table he and his family have always wanted, South Korea gets the rug pulled out from under them, and America gets...well, nothing so far apart from empty promises. Art of the Deal, baby!
It might be stupid, or it might not be. It's entirely possible that Trump, the president himself, can live with Kim retaining some of the weapons he already has for self-defense purposes. Canceling the exercises (without even mentioning it to SK) is just the first step. KJU and Trump have now gotten together and basically agreed on the approach that it will be SK giving all the concessions that Trump and Kim agree to. In Trump's defense, he is an inveterate liar who frequently reneges on promises, so the war games thing isn't a lock.
It doesn't matter what Trump says, or even what he puts on paper. It matters what he will do, and keep doing for the long term. And if there's anything you can learn from his entire history as a businessman, it's that he doesn't stick to any agreement for very long after he perceives some benefit to himself of breaking it.
And I can guarantee you Kim know that perfectly well. It's not as if he was secluded away in isolation his entire life in North Korea.. he attended a Swiss boarding school. He's been at the tip-top of the elites from day one, he's always been aware of the real status of his country relative to others, it just doesn't concern him as long as he stays king of shit mountain. That's what victory is for him, it's not nuking the USA or South Korea or Japan, bellicose rhetoric to that end is purely a means to an end.. his regime remaining firmly in power. He's achieved more in the past year to cement his status among his people, especially the military elites, than he could possibly have hoped. He's being met with as an equal, the US caved on its long standing policy of not rewarding bad behavior with splashy diplomatic initiatives and he has tons of footage of himself being treated with respect by other world leaders. He's going to keep his nukes. He might agree to some arbitrary but pointless limit (like 50, or whatever... ), signing some formal peace treaty and re-positioning his conventional forces slightly further from the DMZ. For those returns I don't consider what we've already given him worth it.