“In Japan we had to learn to like bread. At the start we used to sweeten it with bean paste, we thought French bread was too crispy, so we made it softer to suit our palates”
Chef Yoshihiro Murata, quoted in Sushi and Beyond
Certainly seems to make sense as a historical explanation, as you can now find far more authentic French bread in Tokyo than you can in London. I do think there are other factors, though. One thing is that bread (and the other things that “pan” mean, such as pastries, and in fact most Western food) are still a mainly for females. I’ve written elsewhere on why I think this explains the soft and fluffy bagels.
Another thing is that “localised” bread is the same over most of Asia, e.g. Korea and Thailand. In Korea, for example, garlic toast has icing on it (!) As well as matching local tastes, I have a feeling it had something to do with the people they were getting it from, being sailors coming off long sea journeys. I’m thinking something like the story of how IPA has the taste it has because it was made to travel, but still have to do some work on that theory I reckon…