The two companies are not the same; their dominant positions are in different markets which means the anti-trust implications of them extending into a specific market have to be judged separately.

As an extreme example, Oracle had a dominant position in the enterprise database market in the late '90s, but it wouldn't have been an abuse of that position if they'd integrated a web browser into Oracle 8.

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.

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.