40 or more years ago, the big hifi brands were racing to get total harmonic distortion down to 0.05% or less. The average person is unlikely to complain if it is 5.00%.

There was once a hifi show at which one of the most revered hifi reviewers gave a talk and played some samples for the audience. Almost all the audience noticed at once that his samples had a defect, a loud high-frequency tone somewhere around 10,000 Hz. He didn't hear it.

The concept of good enough has won. Many consumers still think that HD radio is high-definition. It is hierarchical digital, a standard developed to be good enough that most people would not complain. And, speaking of HD, lots of HD TV buyers were perfectly happy even though they were unaware that they have not got their TV producing HD pictures.