Bill, I own two sets of studio monitors, a Genelec and an NHT. So this is not meant to put down the category. I feel however that you are going too far with your argument here. The notion that marketing people portray a speaker other than what it is happens but in this scenario that is not what they are doing. They are showing them in their intended application -- near field.Speakers are designed for a target market segment. Then the marketing people concoct a way to characterize their product. Once a market gets structured with a set of categories like near-field and mid-field, it is advantageous to use those well understood terms to characterize any new product in that market.
Just because companies describe a monitor as a near-field monitor does not automatically mean that it has no value outside the segment the marketing people chose.
You ask how a design can be near field yet not be good at mid to far field. Here is a bit from Wiki:http://en.wikipedia.org/wiki/Near-field_monitors
"The sound field very close to a sound source is called the "near-field". By "very close" is meant in the predominantly direct, rather than reflected, soundfield. A near-field speaker is a compact studio monitor designed for listening at close distances (3’-5’), so, in theory, the effects of poor room acoustics are greatly reduced."
What this means is that if I know my customer is going to sit close to the speaker and with side walls presumably far away relative to my listening distance, perhaps I don't care as much about off-axis sound and can choose to compromise there. I also know I am dealing with professionals and not random consumer which are more likely to listen to the speaker on axis.
The marketing requirement therefore can and does influence design of the product. Is there an automatic exclusion? No. But it does mean that in a generic discussion like this, one can make the argument that if you use the speaker outside of its intended market and application it might have issues. The responsibility then is on the shoulders of people advocating otherwise that despite them having no motivation to make the speaker general purpose, they indeed did. I think you are trying that with your mention of graphs and such but more explanation needs to go there to show that.
I gave you some above .I can be convinced by arguments based on theory or arguments based on sound experiments. I am rarely convinced by reasoning not grounded on theory or experiment. And rhetoric like that in the last sentence is even less convincing.
I do find near-field monitors to be superior to hi-fi speakers in some categories. Bass response is definitely one relative to their price. Bi-amping also means they handle power and clipping in a very graceful manner. Being small and not trying to do everything means that they can have a much more optimized response since the room loading is not as high. In general, I find near-field monitors more accurate and not optimized to sell in a showroom as consumer speakers often are.Your logic doesn't show that near-field monitors would not be acceptable for listening at mid-field distances. Comparing near and mid-field monitors in a manufacturer's product line shows obvious advantages for the larger, more expensive mid-field models: higher peak sound levels (at 1m and thus higher levels elsewhere in the room), better low frequency response and more power in the included amps. A mid-field monitor may have advantages over a near-field monitor for mid-field use but that doesn't mean that a near-field monitor is not suited to uses other than near-field listening.
Bill