As with all things in life...."it depends". As someone else said there are no absolutes.
MOST untrained fighters will attack the head and headhunt. You can find other stuff... sure. But, as a starting point for a beginner dealing with a right roundhouse punch should be the first to learn to defend against.
All fights go to the ground, or even All fights start standing up. Both are false, fights can start and end anywhere. As most people are aware now the stat about 90% of fights go to the ground was based on LAPD use of force where they purposely try to take a fight to the ground to handcuff. But, many fights do go to the ground either on purpose or accident.
You can tell if someone knows how to use a knife by how they hold it. Nope, different tactics and strategies will dictate if it is in their lead hand or backhand and type of grip as well.
"Pressure points" always work or never work. It's somewhere in the middle. For some people they work very well against and other people they don't. Training should be spent at least learning to find and strike the easiest most accessible with the most bang for your buck.
If you are a woman "pee yourself" to prevent a rape. Load of crap. If it happens it will happen naturally, but I have yet to see a case where someone did it on purpose. We condition ourselves so much to hold it that it would be very hard to overcome that conditioning. Add in to that the high stress of the situation and the body has pretty much shut down that non-essential function. Which is why if it happens your body did it naturally as a fight/flight response.
If someone has a knife, I'll just shoot them. Probably not. Most people don't know they are in a knife fight until too late. The old "21 foot rule" is greatly misapplied and misunderstood.
All streetfights are evil people intent on killing you. Could be, probably not. The term "streetfight" is too nebulous. Are you talking about two guys squaring up and agreeing to fight through their words/actions? Are you talking about one guy pushing to fight over some perceived insult? Are you talking about a criminal assault? Not to mention, where do you live and where is the event taking place? Much different mindset in a high end suburban local watering hole and it is two drunk guys versus an inner city street corner.
Combat sports prepare you for the "real thing". Maybe or maybe not. They provide better preparation usually in physical conditioning and the fact that you are applying your techniques against an uncooperative person who is trying to do the same. But, for kicks and grins spend some time on youtube watching pro boxers having pre-conference fights. Looks NOTHING like they do in the ring and you wouldn't guess they were professional fighters. It looks like any other schoolyard brawl. Emotions and anger GREATLY change the dynamics and training goes out the window.
Traditional martial arts prepare you for the "real thing". Maybe or maybe not. It all depends on how they are trained as well. If you only do compliant training and not add in realism, then you can be very surprised when it doesn't go as planned.
The list can go on and on...