Just imagine if in the middle of a rear naked choke they are also tearing your eyes out.
Again, you have a very short memory or just too painful to see. Watch this video again, it explain why it's effective against grappler.
I actually watch your video you posted and practice.
To me, the key of striking is punch high so your hands are up, then the 2nd and 3 punch go to the stomach to drop your hands. Then I practice pulling both hands back high as if to protect my face and body dip down and step back.
The point is I put my hands between my upper body and the grappler to make it harder to try to grape me high like in the video. Then dip body and step back and see whether the grappler can hold onto my body weight.
This is NOT like technique specific for grappler like most of the school teaching. This is how boxer should do in real fighting.
1) PUNCHING HIGH AND LOW TO THROW OPPONENT OFF THE GAME.
2) IMMEDIATE PULL BOTH HANDS BACK TO PROTECT FACE AND UPPER BODY( this serve to put hands and arms in between the opponent and me to make it hard to be grapped).
3) Further dip body down and step sideway or back to slip out of the grappler. These are just simple boxing technique, but should be effective against grappling. USE BODY WEIGHT AND PUT HANDS BETWEEN ME AND THE GRAPPLER.
These are not like those STUPID technique usually taught that if people do this, you step left(or right), then use hands to push this and that those complicated movement. My technique is NATURAL RESPONSE, USING BODY WEIGHT, HABIT OF HOLDING BOTH HANDS UP TO PROTECT THE HEAD AFTER PUNCHING AND WHEN WALKING AROUND. NATURAL.
Also, when I dip down, my legs squat down a little like a horse stand while stepping back to put the center of gravity low to make it harder to take down.