Anthropic and OpenAI don’t care about Math and the progress in that field: They just picked a domain with a lot of cultural capital that is so complex and abstract that people don’t really understand what’s going on.

I don't think this is true at all. A lot of people who work at places like OpenAI and Anthropic or any research lab really, aren't just CS people, there are a plenty of mathematicians and physicists, etc. and so the problems are interesting to them.