Why is Nadella suddenly preaching the gospel of modularity and decoupling of different layers? Because Microsoft controls the harness (VS Code, GitHub, Azure AI Foundry) and the context (Microsoft 365, enterprise data). What they do not own outright is a frontier model. If the industry structurally integrates the model, the harness, and the context, Microsoft’s right to lion’s share of the profit pool can be legitimately questioned. Nadella needs the model layer to become a commoditized, interchangeable plug-in so that Azure’s orchestrators and development tools can capture the profit.