Earlier quoted context omitted.
Eh? Have you seen the mess that is the British measurement system? Distances are in meters if they are short, miles if they are long, Leeds will be 275 miles away from your gas station that would charge you by the liter so would be most other liquids unless they are milk or beer, then you’ll get a mixtures of metric pipes with inch threads and inch pipes with metric threads, when you buy a property the land would be…
Things like threads sizes staying imperial makes sense to me. I believe they are now technically defined in mm, but obviously it's still based on fractions of an inch. In my view, there aren't any truly compelling reasons to switch from BSP to something based on natural metric measures. On the other hand, if we were to replace these pipe fittings with metric, we'd end up with a mixed system for realistically at least…
It hasn't stopped the conversion of most other aviation measurements to metric. Runway dimensions, visibility and separation distances are in meters, temperatures are in Celsius, atmospheric pressure in hectopascals, fuel is in litres, mass is in kilograms. Frequencies are in Hertz. At least that's the case in Australia. Pretty sure Europe is similar.