Re: Self-defense art?
I could be wrong in my interpretation of the question asked regarding Aikido/MA in general and self defense, but I took it to mean an attack on the street from "joe punk".
George Ledyard Sensei approached vs. another trained martial artist instead.
My only encounter in street self defense was in the early 90's after a year or two of training in Tae Kwon Do and ended in a matter of seconds with my attacker unconscious on the ground.
In my humble opinion I would say in Aikido, or any art, the more time you dedicate to training will obviously speed up your learning curve to being able to effectively defend yourself on the street.
How quickly will that occur with dedicated (3 days/week) training? Again, my opinion, I would estimate the timeline at 1 year give or take a little.
Against another well trained person in a different style of MA? I don't feel qualified to answer that.