The Multi-Model Margin Curve: Why AI Infrastructure Choice Now Sets Agency Gross Margin

Frontier model pricing is falling fast enough that the infrastructure layer, not the model itself, now determines whether an AI retainer holds its margin. Agencies that route client work through a gateway with caching, fallbacks, and per-client cost telemetry can reprice deliverables every quarter; agencies hard-wired to one provider absorb every price move and outage as a margin event. The strategic work is orchestration, not model selection.