There's companies out there with mid 8, possibly low 9 figure monthly AWS bills. In that world, letting people pay through said AWS pipeline gets rid of so much red tape. Supporting Bedrock was already a big winner vs OpenAI in the race for big enterprise, and Anthropic desperately wants to find any way to be sticky, as opposed to risking companies flipping a switch and telling entire departments to switch to any future codex + GPT on Bedrock plans. The harder it is for you to migrate, the better for Anthropic.