This strategic analysis portfolio develops a system-dynamics model of the U.S. semiconductor supply chain spanning 1990–2025. The framework integrates fabrication capacity expansion, yield learning, workforce formation, advanced packaging throughput, and industrial policy interventions into a unified system structure. The analysis demonstrates that semiconductor supply instability is not primarily driven by insufficient capital expenditure, but emerges endogenously from long construction delays, cumulative learning effects, ecosystem concentration, and downstream bottlenecks. Simulation results show that fab-focused subsidies provide limited short-term relief, while ecosystem-aligned investment strategies yield superior long-run resilience. The work is intended to support semiconductor manufacturing planning, capacity strategy, and industrial policy evaluation by emphasizing directional system behavior rather than point forecasting.