My thoughts:
After 1970, or perhaps a little before then, the medical profession upped their 'fake diagnosing of 'fake' diseases and would then prescribe rather harmful drugs as 'remedies'. The premise was that the disease was slowly fatal, but the medicines would halt the 'natural progress' of the disease. Not necessarily the doctos' fault, as medical schools were teaching this stuff.
Also, many things harmful to humans and to the environment was either started or stepped up.