There is no evidence that the prospect of death or prison deters the gang members in anyway. Worse there is evidence that getting tough on drug crime, makes things worse. Prison encourages gang membership. Indeed, in many parts of the world you need to be gang member in order to survive prison. Take the example of Brazil. Inmates join the gangs, e.g., Sao Paulo's PCC, for protection. The gang charges an entrance fee which the inmate has to work off by doing the gang's bidding when he is on the outside. If the inmate does not follow through, he and his family are in trouble. That is how a gang grows from a couple of dozen members to one that is thousands strong. If memory serves me right they PCC has over 40,000 members.
Of course the problem is not isolated to connections a prisoner makes on the inside. Someone who goes away for a long stint has no savings, no job contacts a huge hole in their resume and that is just the beginning. Ex cons are hardly in high demand and someone who is on parole has limited freedom of movement; they can not always go to where the jobs are. Not surprisingly many ex cons return to criminality as means of trying to support themselves; what was once a choice morphs into a necessity. If you get a critical mass of these ex cons in particular area, then it becomes particularly difficult to root out the problem. This is especially so if, as is often the case, the drug trade in that area is controlled by a particular ethnic group or groups. Not only does proximity play a role but then so too does family and culture. As is the case with many Mexican, the US, and Brazilian inner cities and suburbs, the risk is that various Canadian suburbs and inner cities will be lost to the drug war.
Prosuing a war on drugs is also hugely expensive. Much of made of the cost of mandatory minimums drug sentences and the policing costs generally. Prison costs in the US are approaching the amount spent on post secondary education. However, court costs are also enormous. There is huge volume of drug charges and the number of drug crimes is sky rocketing. If memory serves the number of drug crimes as gone up 55% since 1994. Moreover, drug dealers and people charged with impaired driving are generally the only kinds of criminals with any money.
The marijuana industry is of such a size in BC that the province has decided that pursuing each and every case may lead to the complete breakdown of the justice system. Th system is literally going to pot. Other provinces will soon experience similar problems and so do not be surprised to see other provinces introduce measures that will allow them "prosecutorial discretion". Quebec will likely be the first. Production in Quebec has surpassed production in BC. The marijuana industry is growing like a weed there.
Finally, and to add insult to injury is that so called successes in the drug war often result in violence; associates or rival gangs seek to fill the vacuum caused by a major drug bust and subsequent arrests.
As to Liberals claim about community programs helping lessen the problem, yes that is true. They do help. However they can only ever go so far. The main reason people sell drugs is simple. There is a lot of money to be made. The only effective way of dealing with the problem associated with marijuana trade is to legalize marijuana. If Canada were to legalize marijuana, the gang world would down size. There would simply not be the need for that many members. Members who ended up in jail or are dead or who simply moved on would not be replaced as fast as they once were. More importantly, the market would not be large enough for fledgling groups to build up enough capital, cache and connections to survive. It should also help in other areas. The gangs are using the proceeds of marijuana sells and sometimes marijuana itself as seed capital they need to branch out into other endeavors.