Because people have figured out that with the billions and billions spent since the 1970's, except in a few targeted cases (mostly focused on either prevention, or early detection - like breast cancer ), the survival rates for almost all types of cancers has barely moved at all...

Having lost family members to obscure forms of cancer (no they were not smokers, heavy drinker etc, white collar jobs, etc.), the path is mostly set after the diagnosis comes in.. hours, and hours in chemo, radiation, etc, all with the same result..