Reviews are most definitely not a substitute for personal experience / auditions. My own answer to the question is a combination of a couple points made above - first, that audio components are reviewed mostly as individual components, but behave in the context of a full system, and second, that most products are, indeed, at least pretty good, and therefore fairly difficult to be negative about.
Still, every review magazine is dependent on advertising for its survival. The audio rags constantly tell us of the separation between editorial and ad sales - ie, no conflict of interest. And yet, I regularly read a review of a component where the reviewer clearly isn't particularly thrilled, but any comments get so watered down that it comes out, at worst, as a back-handed compliment. Maybe it's this way with review mags for higher ticket items. It just seems that you read the comment, "can't match the performance of this $2K amp for anything less than $4K!", but you never read the comment, "This $4K amp is excellent, but you can get the same performance for half this price elsewhere. Therefore, while I like this amp a lot, it's not a particularly good value." Maybe I'm expecting too much.
Still, every review magazine is dependent on advertising for its survival. The audio rags constantly tell us of the separation between editorial and ad sales - ie, no conflict of interest. And yet, I regularly read a review of a component where the reviewer clearly isn't particularly thrilled, but any comments get so watered down that it comes out, at worst, as a back-handed compliment. Maybe it's this way with review mags for higher ticket items. It just seems that you read the comment, "can't match the performance of this $2K amp for anything less than $4K!", but you never read the comment, "This $4K amp is excellent, but you can get the same performance for half this price elsewhere. Therefore, while I like this amp a lot, it's not a particularly good value." Maybe I'm expecting too much.