The South Korean Demographic–Economic Endgame: A Cross-Disciplinary Model of Post-Industrial Systemic Collapse, with Emphasis on the Real-Estate Cascade

This paper treats South Korea as a leading natural laboratory of terminal post-industrial demographic-economic collapse. With a TFR of 0.80 in 2025 and a net reproduction rate of about 0.39, the population has a stable half-life of roughly 25 years and negative momentum makes reversal on policy timescales near-impossible. The first hard, dated manifestation is projected as a real-estate and financial cascade, with a critical window in 2055–2060. The analysis combines demographic mathematics, phase-transition physics, fold-bifurcation and percolation models, pension arithmetic, and Tainter-style complexity theory. Independent clocks—dependency inversion, jeonse rollover failure, and National Pension depletion around 2055–2064—converge on the same window. Six amplifiers, including gender antagonism, labour-force erosion, robotics limits, performative policy, migration weakness, and defence-base decline, act multiplicatively rather than additively. The conclusion is that Korea is not facing a slow managed shutdown but an accelerated, hysteretic systemic collision, with the wider OECD differing in timing, not direction.