Yoon proposes unification by absorption, not by uniting two equals. His "vision" primarily focuses on challenging and inducing change within the Kim Jong Un regime and influencing North Koreans. It's a plot to consolidate his pro-Japan, pro-US, ultra-right forces and instigate war with Pyongyang.
North Korea insults Yoon and threatens to annihilate South Korea. Yet, the South Korean president is reaching out to his neighbor to promote people-to-people and cultural exchanges to create a free and unified Korean Peninsula, which would ultimately end the North Koreans' misery and despair.
Yoon's offer isn't feasible under current realities. Locked in acute confrontation, liberal South Korea and totalitarian North Korea don't share the same culture, language, identity, and history — preconditions for reunification. Seoul and Pyongyang would be better off peacefully coexisting as separate political entities.
There's an 8% chance that North Korea and South Korea will be recognized as a unified sovereign state by 2045, according to the Metaculus prediction community.