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In a nutshell, the main reason is that your home is no where near as bright as these ultra bright stores, and I don't know of any home that uses Sodium Gas bulbs to light the house either. Environment plays a huge part in how good a display looks. This is why I recommend LCD in a very bright room where light cannot be controlled with blinds or dimming the lights, IF they watch most material in daytime. At night and in lower than very bright light levels is where plasma shines well above LCD in most of the important aspects of PQ.
A second reason is that very bright & over saturated colors is not accurate to the source material. Most seem to like "pop" that is not faithful to the source material until they realize it looks more cartoonish and then they look to get the most accurate & natural picture as they learn more. Some will always prefer that overly bright & overly saturated color and for them an LCD might be the best choice though. It is not like you cannot do that with a plasma too, but not to the same degree as you can with a LCD.
What I tell people is to look around their home and in their life and see if they see the same kind of "pop" they see on the HDTV they have or want. True PQ to the source material is what we (most) strive for, and plasma provides that. There is a reason that the Pioneer plasmas come out on top with any display they face in a pro shootout.
