With no effort to engage in a AM pro or con argument, Kana, the exact same could be said for a wide variety of components, including mega-buck amplifiers. Heck, with the cost of some, they should cleanly power themselves without a cord.
I have to agree with Warren in respect to the fact that what does not work for some WILL work for others. Any of us could look at the system of others, pick out a component, say a phono stage for instance, know from experience that it wouldn't cut mustard in our system, and reject it out of hand. But that wouldn't be fair.
I will agree with the need for "wall and behind" improvements. I did install a dedicated line to good effect. And, the very BEST upgrade I have over done in audio on a cost/improvement ratio basis was to install a $40 cryoed Hubbell outlet. Amazing, the difference.