When it comes to the war on drugs there's a perverse incentive problem - said war provides endless amounts of easy to catch/prosecute crime which can be used to meet & exceed their performance targets without much effort. So there might not be too much incentive to kill this "cash cow" of low-level users/dealers by actually curtailing upstream supply.

This might not be too different from the payment anti-fraud industry (which is just varying degrees of snake oil). There are solutions that can be implemented such as actually strong two-factor authentication that could cut down on payment fraud dramatically but this would significantly reduce demand for this industry, so a lot of the field has a monetary incentive to keep the underlying primitives not so secure as to keep demand for their snake-oil.