... which is a natural result of such an obscure system that is needlessly complex for everybody involved. If you can't do conversions on spot as a population,

... which is a natural result of such an obscure system that is needlessly complex for everybody involved. If you can't do conversions on spot as a population, you simply over time don't do it and this state becomes natural. Just like for us literally everywhere else in the world we convert and literally everybody with even very subpar intelligence can be discussed with in such units. Suffice to say, we had tons if very similar obscure systems in medieval Europe, even my tiny eastern country had at least 6 with various absurd conversion schemes for lengths, volumes and weights. These days we go to museums or medieval wiki pages if we want to see that. The thing is, we moved to modern era and absolutely nobody looks back. I suspect with US its more an ego thing and swallowing pride that somebody else can he it simply better, rather than anything else. I mean whenever US actually needs to do some proper science and achieve great stuff, it turns quietly to metric/liters/kilograms. We have 10 fingers 100% of the time right in front of our face and everybody learns to count on them first, there is really nothing more natural.