Four structurally different business models compete at the optical-assembly layer, each with different economics. None is obviously superior — the neutral assembler wins on trust, the integrators on capture. The component maker keeps laser‑attach captive; the full‑stack spans substrate to system; the module assembler integrates upward for supply security. Independent research treats their coexistence as evidence the assembly layer itself is the scarce resource, not any one configuration. Every architecture still needs aligning.