Microsoft pairs GPT and Claude as interchangeable components in a single workflow. Meta considers licensing Gemini because its own model can't keep up. Apple opens Siri to every chatbot via an Extensions marketplace. The pattern is unmistakable: the companies that sit between users and models — not the labs that train them — are positioning themselves as the durable layer. The frontier labs are becoming suppliers in someone else's platform play, and the IPO race between Anthropic and OpenAI may be as much about locking in platform status as it is about revenue.