I cannot speak for others, but she is not to my taste. The music I like has to have more direct relevance to people and events and circumstances and real life out there, to make me think and question and feel diverse sentiments. For relaxing, I find others like Enya and Loreena McKennitt much better. For me, Vashti is somewhere in the middle, neither meat, nor fish. But that's just my personal taste. Perhaps others feel the same, hence her limited popularity.