I have sent my novel to thirty agents and publishers and counting, and obviously all have rejected it or I wouldn't be writing to you! A lot of the rejections say the same thing. They compliment me on my writing, tell me the novel is "evocative", "atmospheric" and "page turning", but none of them know who would publish it so they pass on it. The novel is set in the music industry of the US in the 80s and 90s and I am wondering if this is the problem. There don't seem to be many books published using the music business as a setting and I am wondeering if there';s a reason for it.
Any light you can shed on this perplexing topic would be very much appreicated.
I would definitely say that the topic is not the problem. If anything, I'm slightly interested by the idea. And clearly your query letter isn't the problem if they're complimenting you on your writing, which I'm going to take to mean that they asked you for partials and fulls.
My only conclusion that can be drawn without reading the manuscript itself is that it's not quite there. Maybe the plot needs tightening, or has a weird ending. Maybe the writing isn't good enough to hold up the material. A lot of novels don't end well - this is a comment complaint of my boss, who requests a lot of novels and represents very, very few. This doesn't mean happy vs. sad, this means there's something in the last 1/4th of the book that doesn't work, often because the author has trouble with climaxing the story. I'm not saying that's your problem, but there is a problem. If an agent requested a full, and rejected, it is fair to email them to ask them what they didn't like.