1. This is all a show, a photo op, a Potemkin Village, a pantomime. Both of these dishonorable leaders need to burnish their bona fides at any cost. South Korea is the only honest broker in the show.
2. The Libya model makes it impossible for Kim to denuclearize. Virtually no chance whatever that he’ll do anything substantive to disarm.
3. The Soviet model is kind of forgotten, but it’s remembered by the leaders of every prison camp country. Kim will never loosen his grip, relax anything, open anything or allow the Korean version of glasnost. The very survival of his dynastic rule depends on the absolute subjugation of the North Korean people. Even minor exchanges of citizens or sporting competitions are dangerous to nations like Kim’s. Actual free and open internet would destroy the walls and fences three generations of Kim’s have constructed. North Koreans are kept hungry, not just because of a lack of food, but as a way of keeping them weak and dependent. Such a leader isn’t negotiating even an inch of barbed wire away.
So no i’m not optimistic. Optimism here would constitute insanity.