Why don't health funds

cover something like radiotherapy? 
There is a piece about this in the state newspaper this morning and it is timely. Yesterday I spoke briefly to the  husband of someone who is about to start post surgical treatment for cancer. 
They are both retired, own their own home, and have top level health cover. It's still proving expensive. If she was having radiotherapy rather than chemotherapy then it would be even more expensive.
I had a reminder look at what my health fund covers. It covers things I know I will never use. It covers "homeopathy" of all things. It is coupled with "naturopathy". "Chiropractic" and "osteopathic" are also coupled together. You can get a refund for "Pilates"  and "Acupuncture" and other things as well. They seem to have stopped covering "Iridology". 
There are also the more usual things like Physiotherapy, Podiatry, and Dietary consultations.
Middle Cat was, until she "retired", a physiotherapist. People told me she was good at her job. She certainly had a thriving practice. Knowing they were going to have shoulder or knee surgery or some other surgery people would book her post-surgery services weeks in advance. Fair enough. She will still see a few old patients, especially if she believes it will keep them safe in their homes or mobile a little longer. People believe in her - even though she will give them exercises to do and stern warnings about the consequences of not doing them. Middle Cat can be a bully, albeit with the best of intentions.
I suppose some of it works for that reason. But to fund something like homeopathy and not fund radiotherapy which is considered much more mainstream? I wonder about that?
Being seriously ill has major financial consequences. If you are still at work, struggling to pay a mortgage, bringing up a family, and any number of other things you don't need your health fund to say "we don't cover that" of a major mainstream service. 
It makes me wonder...just how much support do cancer patients get? Not much it would seem.