As with most internationalization problems, blame the British. We used this middle-endian format around the time we colonised North America (I guess it does kind of make sense when you're reading aloud). The USA standardised on it, whereas most of the rest of the world (including Britain) moved on to a more logical format.

See also: power plugs. The British came up with a new British Standard plug seemingly every few years, and all the places we colonised use a different British Standard. We are the reason you need to spend $20 on a universal power adapter with 10 different attachments.