I wonder what the cultural ramifications of something like this would be like. Post War, Japan had a big flourish of art and entertainment a lot of it having to do with taking western themes, products, and trends then blending and bending them into a more Japanese aesthetic or creating something that felt new, showing a Japan that was seeing the world in a different way than it had previously. There were also cultural products that were reactions and rejections to Western and specifically American Culture, showing a hostility to the Nation that was occupying them. In a scenario like this does this get turned up to the max. Would there be American Style suburbs outside of major Japanese Cities, Haiku spouting Beatnik poets, Hokkaido Rockabilly? The Entertainment Industry might be wild, big American Studios trying to release localized versions of their films, while small Japanese Studios try for that niche audience, traditional Noh and Kabuki Theater Revivals going for the Traditionalists and eventually earning a spot on the Small Screen filmed in front of a live audience and most likely both sides of the cultural divide making lots of propaganda entertainment both blatant and subtle. The 1970's would probably feature a lot of entertainment telling the stories of young people of mixed Japanese and American heritage trying to navigate a country where they often don't fit in on either cultural side.