Crews can start off small. Then they hire people to work for them. So you can have over 100 people working for you. Associates can come and go I mean really go because they are expendable. Then you recruit new guys.

A lot of associates are thieves. Then they can venture into other things. Like loaning money but they still are thieves. Then they might get into running illegal gambling games. Then they get introduced into deal drugs.

You can hire kids to do strong arm work or steal for you. Things they were already doing for no money. Now someone shows them how to make a lot more money doing the same things.