stfoth and marty, I have a few times made the case for your exact line of reasoning---the difference between conceptual and real world in regards to loudspeaker strengths & weakness and the demands different "kinds" of music (a string quartet vs. a symphony orchestra, for example) place on a speaker, and how those musical demands interact with those speaker strengths & weaknesses. But to no avail---we are apparently in the minority on this matter, and I don't understand why.
Everyone knows and agrees that a race car optimized for the 1/4 mile is a very different animal from one designed for the Autocross, as is a horse bred and trained for similar, same as a runner specializing in the 50 yard dash versus a marathon. Sure, we would all want to be a decathlon athlete, but how many of them are there? How many musicians are highly proficient in all musical styles? Of course a musician should be able to play any and all musics, but how many can? I can't think of any, off the top of my head.
Loudspeaker design is the art and science of compromise, the designer needing to prioritize his goals for every model. Every design has it's assets, and it's liabilities. Every music places it's own demands on a loudspeaker. It is that all music makes the same demands on a loudspeaker that is the myth, not that it doesn't. To anyone who doesn't think a given ability in a speaker must be sacrificed for another in order to achieve an overall goal at a certain price, I don't know what to say.