I will be interested to see what your conclusions are as well. I have a theory that I have as a result of watching the food truck phenomena in San Francisco (a difficult and sophisticated restaurant market) and this would be related.
I figure that people adjust their expectations of food, based upon a variety of factors, but, chief amongst those is not price, but, rather, location and venue. Even a dive joint, because it is 'brick & mortar', suffers from the expectation that the food must be the same every time. There are expecations of permanence associated with a real building. When the same people buy from a trailer, despite the same, or higher costs and even the same location, there is an allowance that they are some how buying "pirate" food and a little variation is to be expected, even desired.
the meat thermometer was so far past the top reading, it read Taylor
"perhaps...but then again...maybe not..."