So DS comes up with 437x improvement, and the evidence that O/A copied them is that they dropped caching prices by like 50%? Really?

What evidence evidence would actually change your stance on this? a formal admission from OpenAI and Anthropic. Yet that's unlikely

Any actual evidence would be worth considering. This is a pretty weak correlation and an assumption, nothing more.

80%. You can't do that unless you significantly cut costs somewhere. The timing is certainly indicative.