My 70's Ford F-1700 was "Made In Japan" as well.
Japanese farms are often on very small plots of land and an average American machine is way too large. Plus, diesel fuel is expensive in Japan and efficiency is very important.
What I find hilarious is, when Kubota started importing their equipment in the early days, many here in the USA couldn't see the market for a small frame, low hp tractor. Kubota proved them wrong. While it took awhile to get off the ground, nowadays, the small tractor segment is a big chunk of the overall tractor market. When you look at utility vs floor space required for storage, The B Series is one of the most incredibly useful pieces of equipment ever created.
I live in an area where almost every other property is a horse ranch. My neighbor across the street has a small New Holland 25hp HST the wife runs all over the place. Another friend has a Deer (with the wonderful Yanmar). The guy across the other street has a B Series Kubota. Thanks to Japanese quality and innovation for making these wonderful machines a reality.