Re: aikido vs jiu-jitsu
You should really try and study with some practicioners of other arts like jiujitsu. You will find the training methodology is not all about memorizing techniques. Muscle memory...yes. Just like in aikido.
I kinda equate aikido to academia. There are business professors that can tell you all about the economic theory of how to make a million dollars...then there are the "drop outs" who can actually do it. They may not understand the principles or the theory, but have the intuition, experience, and the common sense necessary to make it work for real.
On aikido failing: It is nice to have some breadth of experience that can compensate when your "aikido" fails...whatever that really means!