How many gangs (or 4GW organizations) would remain in existence without being parasites on greater society (i.e. funding through illegal activity) or external funding? How many are self-sufficient, dependent upon the legitimate labor and wealth of its members and native supporters?

I wouldn't necessarily equate all black market activity with immoral activity, though it may be proscribed.

Gangs (or terrorist organizations) may have a certain appeal to boys and young men who lack meaningful relationships with fathers or other male authority figures. Participation in gangs does represent male behavior, but we can't separate the moral analysis of their activities from a psychological or sociological analysis of gang members' motivations. The same couuld be said of 4GW organizations, except that some may be operating in weak nation-state, in which they approximate the functions of the government and can be said to be the government of the local community in fact though not in name.

via Oz Conservative: