My recollection is that Zytiga costs about $7,800 a month in the US and about 15% less in Europe. Provenge costs between $85 and $100 thousand for a single course of treatment, which usually lasts about a month. Generic Zytiga is not coming soon. Oncologists will prescribe whichever is the best drug (Xtandi, in my opinion) and insurance and Medicare (Obamacare has nothing to do with it) will pay for it.
Health insurance is not unlimited and the medical care system is broke. There are many drugs which are not covered in many countries only because the cost is too high and most individuals cannot afford them without help.