Why, exactly, do we require a government-run retailer for marijuana?  We've seen from the example with beer that the private sector is actually BETTER, not worse, at preventing sales to minors.  And we've seen from the private pharmacies that the private sector is better at handling controlled substances.  And there is no monetary advantage to having the government run things, a government-run monopoly is just a different means of taxation and the government could collect the EXACT same revenue through traditional taxation rather than the "hidden" taxation of a government monopoly.

So what possible justification is there to make this a government-run monopoly?