The harness (instructions, tools, execution loop, interface) is the primary differentiator for useful AI applications, not raw model intelligence. The same transformer intelligence existed in 2017 but only produced mass adoption once harnesses and consumer interfaces were built around it.
Shifts engineering investment from chasing the newest model to designing the orchestration layer (system prompts, tools, skills, context assembly) where product value and defensibility actually accrue.
For any capability where the underlying engine is commoditizing, the wrapping runtime/orchestration layer becomes the locus of competitive advantage and product differentiation.
The interface and harness are just as important as the underlying intelligence model.
Transformer models existed in 2017, but consumer interfaces and harnesses unlocked mass adoption in 2022.