Gunshots in Ixtapa

If the main problem in Mexico is US policy then Canada should be awash in drug cartels, violence, extortion and lawlessness.

Simplistic thinking.
1. Poverty is a root cause of most of these problems. Mexico is mostly a third-world country, awash in poverty. Canada is a first-world affluent country.
2. Mexico's climate is ideal for growing coca, the cartel drug of choice. Canada's climate is not.
3. Canada has first-world law-enforcement and judicial systems. Mexico does not.
4. Canadian farmers can make a good living growing legal crops. Many Mexican farmers cannot.

I'm sure there are many other reasons. Canada is not awash in these problems for the same reasons most other first-world countries are not. Mexico's problems, on the other hand, are similar to those of many other third-world countries. Can you not see the difference?

Very Little Coca is grown in Mexico, they have been trying to establish it in the southern tip and it has produced poor results. Less than 1 % of the Coca is grown in Mexico, it takes years to establish a Coca plant, in 6 months a pot plant is grown and finished. If the Marines tear up a pot feild it is replanted in months. They tear up Coca plants and years of work has been lost.