Ali was someone who was naturally good at boxing, he practiced like hell because he wanted to be the Greatest Of All Time, and to most people he succeded. Those are two atributes that contributed to his domination of the boxing world, but they are not the same exact thing.

Many of his contemparies trained just as hard as he did, but he still beat them. Did they lose because they just didnt "try" hard enough, or because they didnt have enough "faith"?

No, they lost because they fought Muhammad Ali in his prime.