Nobody says is a real fight. They say it's as close as it gets. Because it's the truth. Boxing is just a punching contest, that's it. As soon as you hold them, the referee stops you.
Have you seen a street fight with no weapons and with no "friends" involved? They do 3 things ( Punching, grabbing and punching and muscling the other to the ground so the can jump on top of them and ground and pound or simply soccer kick them.
MMA is exactly that but done by experts. It's not just punching, there are calf kicks and weird karate kicks because using those gives them an edge over boxers. It's not just grabbing and punching, you have judo throws and all sorts of grecorroman wrestling types of trips and takedowns. And they use wrestling techniques to "muscle" people to the ground and once there there is this JiuJitsu World that they need to understand to survive.
You say you want the soccer kicks in MMA but if you watch the early UFC and Pride events, they were very rare. The truth is that is hard to land those on a person fighting back and often it's just easier to jump on top of them (which you shouldn't do on a street fight because their friends will sucker punch you).
The soccer kick is really a finishing move in a street fight, not part of the actual fight. If they are landing more than one of them, it's because the other guy is done. Which is what you see so much on a street fight because with no referees, the other guy needs to stop on his own once he wins or is stopped by the crown way late.
As for knees to the head. You can see them in ONE FC. They have 40 events a year just like UFC. They are always allowed. They barely change anything in fights. Just another move to be aware that can finish a fight.