Hey RM3,
I like your side by sides and it proves that defoliating will slow a plant down.
That being said, the demonstration in this video is a high yield technique and has been used for years by advanced growers. It is not new but there is an important note to consider...
You are doing a side by side where both plants have enough "space" to get adequate light. These high yield techniques in cages put a lot of tops into a very small area. The only way to make this work is to pull a lot of the fan leaves and allow the light to penetrate into this dense canopy of tops. Will the tops be smaller? Yes. If you took that same plant and gave it "more" space with less defoliating, would it be bigger? Yes. The reality is in a setup like this, that space doesn't exist.
I hope that makes sense. The idea is really to stack a ton of tops in a small area and thin the area around it. The colas will be a little smaller but you'll have a lot of them to make up for it.
I've seen setups that have even more tops that what this video shows. If it's done right, the yields are very nice