I teach aikido and I think your understanding of it is a little skewed. To practise aikido, both tori and uke need to understand what they're doing, definitely. But what you learn can be applied to people who don't know what's happening also, just less safely. I've had a couple of times where I've done this myself (once a kotegaeshi, once nikyo) to people who had no idea about aikido or martial arts (and weren't expecting it). Thankfully I've not had to use it in real violence, but part of aikido is tempering your ego, raising your awareness, etc., in order to avoid violence altogether.
I wouldn't recommend aikido for learning how to 'street fight'. It's too much of a roundabout process for that. Something that gets right to the point, like boxing and krav maga, would be better. But these both have their own weaknesses. Krav maga was specifically designed to be lethal and cause damage with maximum efficiency. It is not the kind of martial art that keeps you out of prison, since half of your muscle memory will be made up of techniques that have no restraint. As for boxing, that's great and you'll learn how to punch and take hits really well, but that goes out the window when you're inevitably grabbed, or they start kicking, or the boxing paradigm is disturbed by any of the million-and-one chaotic things that could happen in a fight.
Not to mention learning how to do well in bar fights is a collossal waste of time anyway. The average person gets in, what, 5 fights in their life, maximum? And those fights, being generous, last about a minute. That's years of training, thousands of pounds, and likely several injuries, to hopefully do better in those 5 minutes that probably won't happen if you just become better at avoiding violence than the average person. Truth is, even if you're really good, if someone wants to stab you up, they probably can. Real violence is just too chaotic. There's not much value to be had, in my opinion, in taking up a martial art to be able to handle yourself on the street.