Yes, but in the aggregate a population's choices are a function of incentives. What perverse incentives operate in the US (I'm not real familiar with the UK) today? The same black-market dynamics as a century ago: Prohibition. Under Alcohol Prohibition, the traffickers were ethnic gangs (Italian, Irish, Polish, and Jewish), shooting each other up in conflicts over territory and transactions. The US murder rate hit its historical peak, as did the police line-of-duty death rate. We quickly realized that Prohibition was a mistake, and repealed it 13 years later. The question is why the War on Drugs has been allowed to continue for more than 50 years, despite equally obvious failure.