It's also that the insurance and medical care markets don't work properly as markets because of a whole host of factors, eg who has the time or knowledge to comparison shop drugs (if there's even multiple drugs that will treat your condition!) and even for the few people that do have the knowledge insurance disguises the true cost for most people. Combine that with the difficulty of becoming a drug manufacturer and the fact that there's only a handful making each drug we don't even have to have coordinated price fixing, if you competitor raises their prices there's very little reason to not raise yours as well because there's either a) no substitute to that drug or b) patients and doctors are shopping by effect not cost for 99% of the time.