This will continue to happen so long as two things continue to exist:
1) diseases and conditions refractory to treatment or cure by modern medicine
2) expenses related to medical care being born by Americans at a personal level
If you look at other countries, there are absolutely people in positions of power who still push quack medicine because of 1), but 2) creates an extra incentive for desperate or overeager people to try quack medicine.
(2) needs to be nuanced, since we're talking about cancer. Medicare has very good coverage. And EU cancer care can have high out-of-pocket costs. 80% of young European cancer patients report financial difficulties as a result.
Americans who lack health insurance or who have bad health insurance that won't cover all but the most catastrophic of claims.
Think about it: you're a person with a chronic condition that's severely impacting your life. Treating or curing it requires doctor visits, medications, or some other sort of expense that you just cannot afford. You see someone say that it can be treated with some cheap, commonly-available chemicals, but "Big Pharma" and the medical-industrial complex don't want you to know about it because it'll put them out of business. All you have to do is pay $19.95 for their book on it.
1) diseases and conditions refractory to treatment or cure by modern medicine
2) expenses related to medical care being born by Americans at a personal level
If you look at other countries, there are absolutely people in positions of power who still push quack medicine because of 1), but 2) creates an extra incentive for desperate or overeager people to try quack medicine.