Economics, for example, has not been well treated on television. Nor has philosophical thought. These topics usually don't present themselves visually at any meaningful level. Following abstract thought usually requires knowledge of a lot of background information that does not come across easily on video. And that's why there is a history channel but no mathematics channel.
History is a story that can be dramatized.
Mathematics must be learned and practiced. I'm not saying it can't be done. But I am saying it usually hasn't been done well, mainly because the medium does not lend itself readily to this kind of information. Unless an intellectual argument can be made with visual evidence, it will be hard to make on video. Almost any kind of intellectual exercise dependent on prior knowledge and the manipulation of ideas has usually not been well handled using television.