Figuring out what makes any product a 'high end audio' product has long been a vexxing subject. In thinking about this over the last 20 years, the best answer I have ever been able to come up with is 'intention'. So in this regard I think I agree with Phaelon the most, although most everyone here has made points that I consider valid.
But even with the idea of intention, products occasionally appear in the mainstream that are so good they qualify despite their humble origins. Radio Shack has produced a few of these, for example their Linaeum speakers from about 10-15 years ago. They were inexpensive but got good reviews. But for the most part, the intention of the designer will be the primary aspect we are looking for.