Because bedrock isn't subsided by anyone. Or at it would be financially insane go do so.

Compare the of bedrock inference on known open source models to bedrock pricing of SOTA models. If the price of SOTA model is 10x qwen3 480B the the SOTA models is max 10x larger. Obviously anthropic Openai etc take a hefty cut from AWS for letting or run their models, so 10x more expensive model is probably only 5x heavy to run.