I'm going off the assumption that gambling, loan sharking and extortion are still the bread and butter of the street guy. And in all three, the key to collecting is violence or the threat of violence.

And I assume that the mobsters with 6-7 figures outstanding on the street have full time thugs on the payroll, whose primary jobs are to intimidate and slap around late payers.

You shit-kicking, stinky, horse-manure-smelling motherfucker you! If you ever get out of line over there again, I'll smash your fucking head so hard you won't be able to get that cowboy hat on. You hear me? Fucking hick. -Nicky (Casino)