There's no excuse for this. In science the international system should be used for all measurements.
I recall we were pretty much set to change in 76' or so and at the last minute couldn't pull the trigger. Canada I heard was a little miffed we balked as they had put everything in place and made the conversion. Since probably 90 or maybe even 95% of Americans can't tell you how long a mile is or how many square feet in an acre I'd say our system is just too difficult to remember to be worth the trouble. Doubt me? How many TBLS in a cup?gallon? About the only thing I have been sure of for a long time is the ton. 2000lbs and that is only because it is an easy number. Not like 128oz in a gal.