When it comes to business, either you play by the rules or you don't play. You don't thwart existing regulations because you feel they are inadequate, you work with the municipal government to either arrive at a compromise or help enact new regulations.
Except that is explicitly not what happens in the drug trade. This isn't just a debate between the ideal and the proposal, it is also a debate between the current actual practice and the proposal. You yourself have said that marijuana is already easily available without these shops. So arguably we are in fact debating between different models of thwarting the rules, one of which is flouting less critical rules, in a less harmful way.