If you cast a film incorrectly, then you're going to be fighting an uphill battle.
People love westerns worldwide. There's something fantasy-like about an individual fighting the elements. Or even bad guys and the elements. It's a simpler time. There's no organized laws and stuff.
Casting a film is to me one of the most important things next to the writing. If you cast it properly everything takes place very easily. If you cast it improperly you're fighting an uphill battle.