The 20% problem: why Taiwan's imported equipment parts still carry 70% of the cost

The 70% imported-parts ratio is not a cost problem—it is a sovereignty gap. Taiwan, China leads in process nodes, yet its equipment layer remains structurally tethered to ASML, Applied Materials, and Lam Research. If export controls tighten, line shutdown is not a tail risk; it is the base case. Technical cascade: insufficient local sourcing of spares directly caps CoWoS and SoIC capacity elasticity. When AI compute demand spikes, the bottleneck sits in maintenance supply chains, not fabs. Competitive response: Samsung is accelerating domestic equipment co-development; Intel's IDM 2.0 is fundamentally about de-risking single-source tooling. China's AMEC and Naura have validated substitution at mature nodes but remain blocked below 7nm. 18-month outlook: expect strategic spare-parts reserves to materialize—logically identical to petroleum stockpiling. Equipment vendors will push service centers into Southeast Asia as a geopolitical hedge. The real unlock is not the domestic-substitution narrative; it is modular architecture redesign enabling multi-source component interchangeability.