If we look at the math problems they're solving their just now reaching the human frontier... they weren't doing that before.
And your comparison point is model released 2.5 months ago... saying for some use case you didn't see noticeable improvement in 2.5 months (even while other people and benchmarks disagree) isn't a great argument that they aren't improving.
Success in such problems does not automatically extrapolate to other contexts.
Jane Street is apparently one of Anthropic's biggest customers. Probably engineering, finance, and some math.
That's the thing I'm most worried about - LLMs that are super clever at coding and maths, making an actually very very dangerous model that is far more efficient, and clever in a more innate (less brute force) way.