I replied to all of that, only to now realize that it didnt come through.
Basically, the summary of what I was saying was that Street Fighting and Untrained are two different things. For example, one of the two martial arts I do pretty much specialises in techniques to be used in the street. While I probably can't do any of it, the sensei and other high grade practitioners would have a very high level of ability regarding it. An MMA fighter might have a guillotine or a triangle up his sleeve, but just because we see that stuff in the cage doesnt mean it's the most effective. Wrist locks are equally as effective, and because small joint manipulation isnt allowed in the cage, an MMA fighter won't have come across it. I believe this levels up the playing field between what techniques will change the fight. Adding to that, an MMA fighter has holds barred, while a martial artist training in a non sports enviroment has none. Eye gouges, groin shots and hair pulling or whatever you mentioned might not be the best techniques ever on their own, or as a counter, but when mixed in with technique and intent they are a lot more damaging than otherwise. The person training for combat on the street will have an obvious home field advantage. Martial arts takes street fighting in, as martial arts was not developed as a competition, but as a self defence system. Everything stems from that, and unlike MMA which is 100% focused to competing, the techniques are designed to prevent threats on your life, not victory. Street fighting isnt the drunk guy outside a nighclub, it's a non disqualification fight to the finish, whether that be by it being broke up or worse. Take weapons in too. An MMA fight will have no clue how to disarm a martial artist with a weapon, let alone defend against it.
It's pretty much what I said earlier. It's only relevent when you take a trained fighter against an untrained fighter. When you're trying to use techniques like a triangle, in which you'll either have to pull guard or use it from the top, you had better make sure it's an untrained fighter. You pull guard on the street, instead of trying to punch you, someone with intelligence could just repeatedly slam your head onto the concrete. You can lock in a triangle, but if they have any sort of martial arts knowledge, you could be picked up and slammed, with a massive chance of suffering a huge injury. If you go for the guillotine, even basic fighters can keep it standing and put it against the cage. Take the cage away. You're getting thrown into actual things. Buildings, cards, lampposts. That isn't going to knock you out but if people can use the cage to slip out of submissions, I'm sure using a solid surface will be a lot easier. Thats what I'm saying that using the natural abilities of an MMA fighter is the best thing to do. An MMA fighter will have more experience in sparring than any "street fighter", because they don't need real life fights to have punches coming at them with the intent of knockout and damage. Keeping it standing allows the MMA fighter to use his reactions and reflexes against the less experiences opponent, but taking it to the ground allows a trained fighter the oppertunity to exocute techniques the MMA fighter has never even heard of.