I have outlined many, many times why drug policy is insane, and how a properly regulated supply-chain, generating taxes rather than spending them on the futile task of interdicting supply, would be better than the current system of prohibition.
For example, it's likely there would be fewer heroin users were a full recreational pharmacy available legally than there are now. Why? Because of the pyramid marketing of drugs is particularly effective for heroin. Users become dealers to fund their habits. There were few problem opiate abusers before it was made illegal, and most of those picked the habit up in hospital. Just try making that argument to a Daily Mail reader.
There is no public clamour for drug reform. Users are people who by definition can already get the drugs they want. Most people are happy that drugs are illegal, and are inherently conservative. And there are vested interests in law-enforcement and the criminal fraternity in favour of the status quo. A simultaneous monstering from the Tabloid press and the immediate threat of assassination by some of the most ruthless criminals on earth? Is it really a surprise when politicians who're known to be privately in favour of liberalisation keep their heads down over something of such marginal interest to most of the electorate, who in any case, have already made up their minds?