Sustainable economic development in Southeast Asia remains a central theme in regional policy debates, particularly regarding the efficiency of factor accumulation. This study empirically investigates the dynamic relationship between physical capital, human capital, labor force, and economic growth in six ASEAN countries (Indonesia, Vietnam, the Philippines, Cambodia, Laos, and Myanmar). Using a Two-Step System Generalized Method of Moments (GMM) approach for the period 2017–2023, the study overcomes potential endogeneity issues and captures the path-dependent nature of regional growth. Empirical results demonstrate a high degree of growth persistence, with the lagged GDP coefficient indicating a strong momentum effect. Physical capital is found to be the primary and most significant driver of economic expansion, validating the importance of sustained infrastructure investment. In contrast, human capital and labor force participation do not have a statistically significant impact on GDP, highlighting the profound "education-growth puzzle" and potential skills mismatch in the region. These findings suggest that despite ASEAN's growth being underpinned by a capital-intensive strategy, the region faces structural challenges in transforming human capital expansion into tangible productivity. Policy recommendations emphasize the need for a shift from quantity-based to quality-based education, as well as better alignment between academic curricula and industry demand to ensure inclusive and productivity-based growth in line with SDGs 4, 8, and 9.