I don't disagree with you that the consumer loudspeaker market is fragmented in term of what they consider quality. We all seem to agree that amplifiers, and BLU-Ray players should be +- 0.25 dB but with loudspeakers, all sense of rational thinking seems to go out the door. I think this has to do with poorly controlled listening evaluations and poor objective measurements because when you have good subjective and objective measurements , consensus is usually reached.
That said, I think there is convergence over the last few years among the larger, more successful audio manufacturers in terms of what they believe the optimal target should be. I know this to be true because I do a lot of competitive benchmarking of loudspeakers, and the differences among competitors have shrunk. They are reading the available scientific literature and the measurement equipment, design tools,etc have come down in cost. Some even have anechoic chambers for doing accurate measurements but they don't always calibrate them or use them to their advantage.
There are still cases, where marketing/sales are clearly voicing the speaker to sound hyped in the bass and treble (Speaker B) and not natural, or they are going for high midrange sensitivity at the expense of bass in order to be the loudest speaker (Speaker C) on the floor at Best Buy. Or in the case of Loudspeaker D they clearly don't have any serious subjective/objective measurement capability or truly believe that coloring/distorting the music differentiates them from the pack. I've argued with misguided marketing people who think accurate sound is boring and not sellable, but fortunately they are long gone, and I am still here.
But on average, the design target for the majority of companies is flat, extended frequency response. The better ones get it right off-axis as well. The differences are how well they achieve their target and the devil is in the details. " Sean Olive Harman international
