I disagree somewhat regarding markets, segmentation, and offering. Both have a Web search function as a headline offering. Both have ad enabled platforms. Both are integrating their AI into office and productivity platforms. Both are running integration APIs for their LLMs. Both are actively engaged in research. Both are large market players.

Breaking one will absolutely give the other an unfair advantage and entrench a market leader, which is against the principles of antitrust.

I can use Anthropic, Gemini, and OpenAI interchangeably (and actually keep the three open as tabs in the same window). This argument doesn't make sense. Monopoly relief should be applied only to monopolistic products, and not strengthen someone else's monopoly.