To say that the technique failed is to say that what you wanted to happen did not happen. Analysis afterward can point to yourself, your uke, or any other circumstances, but the ultimate cause was that your expectation was not met. Aikido could have still happened, but you got stuck.
teach that things go awry---embrace it! Show that when this doesn't work, then we have that. If I lose this, I still have that. Etc.
I think it's a much more productive mental
angle to teach students earlier not to get stuck than it is to perfect a form. I suspect it saves trouble later