> mafia-type organized crime

I'm not clear on what you mean. Surely there are gangs, many of them organized along family or ethnic lines, that control the typical crime markets like the drug trade. It may not be Italian-Americans, but there's plenty of other groups in such a large city.

Maybe they are more fragmented, but they are still basically made of full-time criminals who know each other and use violence to contest the market. In terms of scale, the industry is big enough that people specialize (import / distribution / money-laundering / etc) and so there's an economy requiring its own version of a justice system (aka negotiations, violence).

Isn't that pretty much the same as the mafia?