Why a western?

My upcoming story, Montana Belle, is a western set in (obviously) Montana, in this case, 1880s Montana. Why did I decide to write a western? It's not a thriving genre nowadays. As a standalone genre, westerns per se have practically disappeared from the bookstores. Even as a romantic subgenre, they're relatively uncommon. In a genre dominated by werewolves, vampires, shapeshifters, Regency-set historicals, and suspense, westerns are a distant contender for most popular subgenre. Yet they endure. Why? I have a few theories.
The appeal of the wild west or pioneer days is never-ending. The wild west was a time of few rules and boundless opportunity. Social mores were loose, at least for the time period. Settlers could come from nothing, and, with a little luck and a lot of hard work and endurance, reshuffle their spot in the social order, something that wasn't possible back east. (Montana Belle involves a hero who does just that.) The landscape, wild, rugged, and dangerous, is without a doubt a character in most westerns. The setting is also rife with opportunities for conflict: Rancher versus farmer. Native Americans versus white settlers. Outlaws versus law enforcement. Miners versus miners, and miners versus the elusive metals and minerals they set out to find, often with heartbreaking results.
In addition, the wild west doesn't present the difficulties some other historical settings do. Civil War romances have fallen out of vogue partly because of the difficulty of dealing with slavery, although I still think that the right writer can mine that setting for a great story too. We're more used to seeing movies set in the wild west than say, colonial times, so there is a natural reader familiarity and comfort level with the time period. When you consider the natural opportunity for drama and the unique place these stories have in our American national character, it's no wonder westerns have endured.