Re: why do people outside Aikido for IS?
IMHO, its not a crisis only an opportunity.
Its is not what is lacking/missing (implied that it was there or should be there) only that there may be more.
In FMA we often say that the art is complete but not finished.
But, I have been a cross-trainer and perpetual-student my whole life.
Each person gives/shares what they have; some will appreciate it, some will reject it, and most will complete ignore it.
So it goes.