I read about this. Notice how he was killed right in front of his family. The rules over there are, there are no rules. There was another one killed recently too. I forget his name.

The difference is, it's about honor and respect in Italy, and monetary things come second. They're born into mafia families, their memories are long, they want to avenge deaths from decades ago, etc. They don't wake up and say, "gee what should I do for a living...ok, maybe I'll see if I can get made into mafia."
Who's the last US mafioso boss that held his honor so high that he was willing to go into hiding in a hole in the floor for years? Or hang out in catacombs for years? Or a shitty farmhouse? It's because the honor of what they're doing is first and foremost.
You'll never see that here in the US. Thats why if you're ever in Sicily, you wouldn't know who a mafioso was unless you knew who he was.