I'm not saying this makes sense to -me- I was saying this is what you have to overcome. People created the imperial system after things they could visualize. Over time the system became a part of the culture. At that point its almost impossible to change, in order to hack culture, you have to overload and redefine the symbols and the rituals of that culture. This has been the chief problem with the Metric system, its hard for the common man to know if 1 Kg of a substance for $10 is a better deal that 1 Lbs of the same substance for $10.
Now in order for the metric system to catch on we are going to need to come up with good ways to get people to think in meter, liter, or gram units.
In the United States the Liter is the soda bottle. This is good. The gram... drug use is popular enough among certain groups and but in the states where the legalization process is underway most of the substances is not sold by the gram. As for the meter, we are already making an impact on the health nuts with the 5K/10K runs, but there needs to be something people can get their minds around. 5,000 or 10,000 doesn't work.