One real nuisance is the way that, now, if you are trying to repair some woodwork in your house etc, when you go along to B & Q or wherever, you find they don't have the right sized wood. For example, you want a one inch plank, and they don't do them, just some metric approximation.

"...the system will eventually disappear of its own" Not quite, so long as the Yanks hold firm, and I can't see them going metric in a hurry. Of course some of their non-metrics go a bit strange when it come to their mini-pints and gallons, and they've never caught on to using stones, but linear measurements such as inch, foot and miles should be safe enough.