Our country is not quite that bad, at least not yet. The real issue is that the legalism of marijuana is going to lead to a less productive workforce which means a slower growing economy
Legalization of marijuana does not imply wider use and a less productive workforce. It will only drive the drug lords out of business and result in higher tax collections.
This is not necessarily the case. In CO there have been a number of robberies at drug dispensaries that have been connected to drug gangs.
It also means that people will be able to openly carry drugs after they buy them but does not mean the people will buy drugs legally. This means that drug gangs can sell more potent drugs and does not need to worry about transporting drugs discreetly as the penalty for doing so would be removed