But my point is that people who prefer old units are not being entirely irrational, or averse to change.
It's just that for their particular use case (making human-scale furniture out of wood, for example), the Imperial system works pretty well, and perhaps better than the base-10 metric system.
If they had to spend their days converting between acres and square feet (43,560 of the latter go into the former, by the way), they might be more inclined to switch to metric.
A property of the US customary units is they tend to be more optimized for specific uses at a given scales, with little thought given to changing scales. Metric units make conversion easier, at the cost of often less suitable for use at scale - how many steps does it take to go a kilometer?
Adult males of roman military height, so probably about 5'7" (170cm): http://history.stackexchange.com/questions/17072/average-hei...
Playing Pokemon Go?
Besides, it takes about 10 minutes of walking to go a kilometer. You don't count paces, do you?