Interesting thought, lets examine it. While ambushing Fanucci might not on the surface seem to be courageous, I would submit that, that was the only way to eliminate him. I am sure that others if they had the courage would have loved to eliminated Fanucci. Even though we know that Fanucci, acted alone, did Vito know? Isn't it possible that the reason others didn't make an attempt on Fannuccis life, is because they feared retribution from his family? Vito was in a state of warfare with Fanucci, not out of power or greed, but necessity. Fanucci screwed Vito twice out of money, and in effect was taking the food out of Vito's families mouth. He had enough, and did what he had to do. Did you want him to challenge Fanucci to a duel at twenty paces, or have a Matt Dillon shootout?