I am arguing for the possibility that this is a very myopic view of what these men were after, in the case of Kodo, Sagawa, and Takeda, about which we know comparatively little.
That Taichi guy...who didn't build a house for his family because it would cut into his training time...that's a powerful cautionary image but I don't think it is the proper cookie cutter for the four aiki greats we are discussing.
In the case of Ueshiba, "martial power" was clearly a trivial matter to him in his latter decades. His focus was spiritual. And going back further, what is your explanation for the whole Omoto involvement? Why go to Mongolia? Why get involved in politics? The huge investment in personal time and energy he put into these things, at the expense of training his internal power, really indicates that the martial power aspect was a minor piece of the puzzle.
I would go so far as to say that a solo training / internal power training method cognate to what Ueshiba was doing, followed simply for the benefit of pushing oneself off of walls and avoiding joint-locks and such, is a far more degenerate version of what Ueshiba was doing than Aikikai Aikido.
I disagree that martial power is a minor part of the puzzle - if you look at what Ueshiba said in the context of the training method it is clear to me, at least, that the training is what powered everything else.
If martial training were minor he would have abandoned it. If that had happened, then people like Saito, trained directly by Ueshiba post-war, would have been unconcerned with the martial aspects.
Of course, for Saito it was quite the opposite - he often criticized the way Aikido was done in Tokyo as having lost those very aspects.
Someone can be driven, and sacrifice parts of their life, and yet still do more than one thing. Nobody said differently. Kisshomaru Ueshiba, for example, expressed regret over how he treated his wife and the things that he sacrificed in developing the post-war Aikikai organization. Most people who achieve great things are probably a little bit monomaniacal in some ways.
And I think that solo training is a little bit more than pushing yourself off walls and avoiding joint locks.
I could talk about how Aikikai Aikido is about dressing up in skirts and twirling around in circles - but that kind of comment isn't very constructive either, is it?