I thought the opening paragraph was clear and definitive and worth pasting here. Interesting that he developed a hypothesis early on, that later proved itself out upon further, more in-depth study and research during his time in Japan.
After practicing and researching aikido for a number of years, I gradually arrived at a hypothesis that went against conventional wisdom and the testimonies of numerous shihan who claimed to have spent long years studying at the side of Aikido Founder Morihei Ueshiba. I had over the years attended numerous seminars given in the USA by Japanese teachers, and also made several trips to Japan where I had seen and trained with many of the best known teachers. My theory was simply that aikido as we know it today was not the art practiced and taught by O-Sensei, but rather any one of a number of derivative forms developed by key students who studied under the Founder for relatively short periods of time. This would account for the considerable divergency in styles, the relatively small number of techniques taught, and the absence of an Omoto-like religious perspective in the modern forms of the art. This was not meant as a criticism of these “modern” forms of the art, but rather an observation based on historical research that ran contrary to common perception.
There were folks who studied for aprox. 5-6 years before being sent out to run the aikido programs for whole countries and become the "word" for all things aikido to those they taught.