Also, from a performance standpoint, in most any endeavor there are almost always high performing outliers. And we tend to define the endeavor by those outliers. So all the talk about how we all train to become "like" someone like Ueshiba or Takeda or Shioda or Tohei or (fill in your fave) totally ignores the reality that they were themselves outliers in a strict sense and the rest of us likely, well, aren't.
You make some excellent points. For me, Peter's TIE series, combined with Ellis's and Stan Prannin's writings have engendered a bit of a crisis for me in my training.
Basically, when I started training in the late '90s, I bought into the "watered down translations meant for Western audiences" of O'Sensei's discourses, accepting them as accurate accounts of what O'Sensei believed. I also saw them as guideposts to my training so that I could end up with power and skill like O'Sensei's.
My impression from this and previous TIE articles is that O'Sensei's cultural context and religious beliefs were exceptionally important in motivating his training and development of aikido, but were not the mechanisms for actually developing his martial skill. In other words, one could divorce the "spiritual" stuff from the body skills stuff and (with enough practice) become a powerful aikidoka.
And yet, the so-called spiritual context of modern aikido is so intrinsic to how it is presented, taught, and practiced in mainline aikido organizations that it would be hard to define aikido without that context.
Yet again, the Western understanding of that spiritual context (at least as I've experienced it and read about it), is based on a very incomplete understanding of O'Sensei's discourses as well as later writings by his son that were meant for larger audiences.
So, if we're not really understanding what O'Sensei was saying, and we're not really developing the internal skills (aiki) that O'Sensei said was so important, and if most of us are not able to dedicate the amount of time to solo training that seems to be required, are we actually doing aikido?
I don't know.