1. Using grappling arts defensively is still utilizing grappling.
2. Imagine the havoc grapplers could unleash unloading knees/elbows to the back of the head/other crazy shit to an opponent on bottom.
3. Imagine there were no walls and it was a giant open mat. You can use the damn cage as a tool to help you not get taken down.
4. Imagine MMA without the fucking round by round boxing model. If someone completely dominates you and takes your back, what did you deserve to do to break free and start standing? The clock saved your ass and that's it. If you gain a victory through the clock saving your ass, I wouldn't take pride in a victory like that.
Things would look different if the rules changed.
(1) No it isn't, because the rule do not consider defensive grappling as grappling. Think about the Masvidal vs Maia fight. Maia tried to submit Masvidal and failed. Masvidal defended against the submission and succeeded.
So, who was the the more effective grappler, the guy who successfully defended or the guy who failed to submit?
Some people will say "defense should not be scored, because that is what you are suppose to do."
So, you see, defensive grappling is not grappling as far as mma scoring is concerned.
(2) If strikes to the back of the head were allowed, fighters who are taken down will not give up their backs trying to get back to their feet, because that is often the time when grapplers get their backs.
They will pull guard and remain on their backs protected by the canvas, while the guy laying on top is exposed to strikes to the back of the head, neck and spine.
The guy on top will be forced to advance his position or ground and pound, instead of just laying on top throwing weak shots, so the referee doesn't stand them up.
(3) Takedowns will be harder to get without the cage. Watch Maia vs Masvidal again. One reason Maia was getting takedowns was because he would grab Masvidal in the center of the cage and as Masvidal was trying to defend, he will end up pinned against the cage, making easier for Maia to get the takedown, because Masvidal was trapped.
Without a cage, a fighter with good balance will be very hard to takedown, because there will be no fence to stop him. You will have to push him outside the fighting area.
Taking a person's back is not dominance. As long as I keep both my hands on one of your arms, we could stay in that position for eternity, and you will NEVER get the choke (unless your conditioning is better than mine).
Masvidal showed how to defend against a RNC. Don't worry about the little distracting shots that are more annoying than damaging. Keep two hands on one, and the guy who has your back will never get the choke.
You can't complete a RNC with one arm. I am amazed that most fighters don't know this. They are always trying to fight the little shots, instead of keeping two hands on one.