Pretty sure you are correct about the only Australian based
organisation, but I think the difference is that Aikikai Australia is affiliated directly to the Honbu, where other organizations such as AKI and AAA are affiliated to the honbu via overseas aikikai shihan (ie. Japan (Tekada Shihan) and USA (Nadeau Shihan) for these 2 examples) and can still award Aikikai Dan rankings.
It is interesting that I have trained with at least 2 senior Aikidoka in US who were very surprised that I was not from Aikikai Aust because when they visited Australia with Yamada sensei, they were told by the locals that Aikikai was the only Aikido organisation in the country. May be a language barrier with the Americans and Australian, I find that a lot here
Language is difficult! Thanks for your input. I recently did an instructors course during our national summer school, and we didn't dwell on this point too much. I was much more concerned about not falling asleep after 3 hours of training and a big lunch
I agree that this was probably a mis-speaking about being the "only" organisation. I pass by a Ki Society dojo on my way to training, and I think there's a Yoshinkan one nearby as well. I couldn't speak to numbers or popularity of the different schools, though.
I always noted how closed Aikido was back home, organisations would hold seminars but only be open to members of their organisation. In the US thing are far more open (at least in my limited experience here), I can't think of a seminar I haven't been able to go to regardless of the organisation it was conducted by
Again, speaking with limited knowledge, but I believe it's mostly to do with our insurance coverage. We can only cover people who are "members" of our organisation. How memberships work is definitely material for a different thread. We've done a lot of legal work recently to accommodate as many different people as possible, especially with our 50th Anniversary coming up next year. It's not that we don't "let" people from other organisations train (at least in the dojos I've been to!), it's figuring out how we can cover them (and us) for worst case scenarios.