OK, in case anything is unclear - nobody here ever said Ueshiba or anybody else never took ukemi.
Of course, anybody is capable of taking ukemi if they choose to do so. The can also roll around on without anybody being around for miles.
FWIW, Dan has taken ukemi for me many times.
I don't think it's one or the other ("taking ukemi" or "being thrown"). There is a continuum that ranges all the way from letting a 5-year-old execute kokyunage on you, to finding yourself on the mat and not even knowing how you got there. The latter has never happened to me, but I've felt quite a bit of the scale over the years.
I could see how the possibilities of experiencing the higher end of the scale would diminish (potentially to zero) as one's own abilities (or whatever
) increase relative to those of the people with whom one is training. Under this conception, O-Sensei might experience everyone the same way I experience training with my kids' class.
I think this is the point Chris and Dan are trying to make. It makes sense to me.