The Western

It's an interesting question why the Western is a defining American genre rather than, say, the Colonial American period. There's stuff in Cotton Mather that would make for a great movie or TV drama. Likewise, The Last Mohican is a fine film. 

But somehow that period never caught on. Of course, that's in part a result of the fact that directors prefer films and TV dramas about the Old West rather than Colonial America. 

Yet I think a lot of the appeal has to do with freedom from civilization. Big sky country. Simplicity. 

It's a very masculine lifestyle. 

Westerns also reflect a longing for the past. Something both science fiction and the Western share is a discontent with the present. Westerns are past-oriented while SF is future-oriented. 

Not only can people feel out of place, they can feel out of sync. That they don't belong in this time. It's too early or too late.

SF tends to cut against the grain of religion because, in SF, the "magic" is supplied by advanced technology rather than miracles, witchcraft, and spirits. 

There are exceptions like Frank Herbert's Dune series. Of course, that's "soft" SF. And it reflects his eclectic interests.

Westerns often trade on a man-against-nature motif, where there's nothing between you and a hostile environment. That's in contrast to a lot of SF, where humans live on space ships and futuristic cities. 

In a Western setting, God is the only thing between you and death. You don't have that technological cushion. 

That gives many Westerns a more primitive, elemental quality that can dovetail with religious themes. 

Likewise, the desert landscape lends itself to allegory. 

It has a more "biblical" appearance, like the Mideast. Vast, dry, majestic, but austere and inhospitable.