I have more faith in humanity and the scientific process than you do.
Any treatment that cheap, if published, will be pursued somewhere.
If nothing else, a company could make money by marketing the product appropriately. Or a company could use the cheap cure as a PR stunt / morale booster akin to Proctor & Gamble's
PUR packets, giving it away for free, knowing that if people like their company they'll be more likely to purchase other products from them.