That's the silliest argument I've ever heard. If this is not helpful, then clearly it's a bad idea for low income families to spend 3k on it. They could spend it on something that actually helps. If it's quackery, the false hope it provides is evil in itself. And if they are paying kickbacks to doctors, then clearly it harms the patients' trust in doctors, as mentioned.

As to 10%, the average returns from S&P 500, since 1957 when it was formed, is 10.5%, so 10% is pretty much what you'd expect if you put the money in stocks. Especially over a longer term like 20 years.