Perceptions are one thing. Biased by many factors.The problem is that your use of the concept of "bias" is simplistic...
A bias is not only something to be eliminated in a statistical experiment using blindstest for example, it is also a positive constitutive aspect of perception to be used and developed in a controlled user environment ...
You used this concept of bias in an ideological stance....
Actual technical specs are a baseline to making a purchasing choice.This last affirmation made no sense for me...
For sure i want an amplifier with good specs, but among the immense crowds of those measuring well, are they equal?
No like everybody with 2 ears can know....