The Mafia as a secret society need more of capable men able to run white collar rackets that a men that stone cold killers.For sure there are mobsters that can do both things but are few in this days.
In a "civilized" country like the USA the mafia can't rely on the military that's a no-no. They had to have earners and killers, preferably guys who were both. You can't control people without violence or threat of violence and without a ruthless reputation, forget it, nobody's gonna fear the mob and thus the money flow would be less than what it potentially could be - much more.
