Is Western genre a curse?

I wrote a YA novel based in the 1890s in Texas. Of course the characters ride horses and indeed, they live on a ranch. With a few exceptions query letter responses suggest either the agents don't like the era or it's not their type of material. I've actually gotten several nice, non-form-letter responses suggesting the early chapters submitted are good, blah blah blah.

I'm thinking the fact I put the plot in this 'cowboy' age is making it commercially unattractive and recategorizing what was intended to be simply a young adult novel into the Western genre. If my theory is correct, I've got neither fish nor fowl: not Western literature in the pure sense because of the reader audience intended, and not a good YA book because kids want to read about themselves.

What are your thoughts on a rewrite, keeping the same location and story-line, but pushing the time frame up a hundred years, contemporizing the characters, etc.?

These insights are useful. I hope to read more. In response to that which has already been stated:

I have had several kids of both sexes read this book. They uniformly like it. The problem is, of course, there are very few agents out there that are under 16. My impression is that mainstream YA lit is either Harry Potter/Lord of the Rings stuff or it's contemporary. That being said, agents are looking to make a commission not start a new trend.

This book actually has a quasi-supernatural component - a mystical stone knife that once belonged to a Indian chief. The knife happens to be in just the right place at the right time to help the protagonist work through various issues of adolescent inadequacies, etc. The problem is that I can't get this mystical stuff moved ahead to squeeze it into the first three chapters, which is all I can get any agent to look at (even if I slip in a synopsis!).

Finally, in my frustration I have now begun the revision of this book I mentioned, moving my characters ahead 100 years, creating more of a 'Last Picture Show' quality to their lives in west Texas. The read is still pretty good in the new setting, with about 125 pages done. But I am now so emotionally attached to my initial story line I'm losing objectivity.

And by the way, my last gasp of effort with the old version was to bypass agents and send queries to few publishers of regional literature. Trouble there again is that few are into young adult material. Still waiting to hear from them.