Maybe there is a reason to keep using difficult units so that everyday joes won't want to understand stuff like science/engineering and just be skilled workers with not much thinking and be happy with what's given to them (my conspiracy theory again).
Having taught college physics for the past 10ish years, I really hate how much the US has embraced with metric units...
Except for you have it backwards. If I'm following you, you're saying American Standard is hard and metric is easy.
But in America, skilled labor (carpenters, metal workers, etc... you're average joes) use American Standard (the hard measurement system) and engineers learn to cope with metric (which you say is easy).
You say you hate teaching metric units to college physics students... who are those students? I'll bet 85% are engineers unless you teach some crazy branch of physics. I remember learning everything from vectors to modern theoretical physics, "Einstein stuff." We did Statics and Dynamics... you name it, Engineer students learn it... in metric. But when I was a metal worker saving up money to go to school I used American Standard daily. It's just what we grew up with and what we use for building thing over here.