Usehiba, M. - "One does not need buildings, money, power or status to practice the Art of Peace. Heaven is right where you are standing, and that is the place to train." The Art of Peace, John Stevens, p. 14
I haven't seen anything related to Aikido as a vehicle for the transmission of Japanese culture. In 25 years with Maruyama sensei he never once indicated that cultural transmission was in any way relevant to our training. The dojo, clothing and rituals provide a cultural context in which training takes place but I don't see how they contribute, or their lack detract, substantively from one's ability to coordinate mind and body and get on with the business of studying Aikido.
I agree that Aikido would be a poor vehicle for the transmission of Japanese culture.
Hmmm...25 years is a really long time to train under a teacher. Question: can you bring to mind everything you have learned from training under Maruyama Sensei?