Have seen that video before. Conclusions are what they are... for that one engine. And that may be the same for many high end engines that don't work hard in the bike they run at any time, as stated by this guy. There are a great many different engines in many different bikes. Some never work hard in the bike for which they are made and others are maxed out just running normal speeds. Engines and engine parts ARE better made these days compared with many many years ago. The last half of this video is actually more relevant to the discussion than the first half. Testing one engine, as in the first half, gives one result. Testing a dozen of the engines out of the best bikes in the industry, and then also a dozen of the engines out of the worse bikes in the industry, may very likely give different results than this one engine did. While I agree that most likely the top end components may not give different results regardless how that engine was broken in there are a great many other parts that were never compared in this test and possibly would benefit from an easier break-in. Ari Henning didn't look at those other parts. He also did not mention how the ring gap differed, only that it did. He did mention some really good reasons to follow the break-in process recommended by the manufacturer. Making sure there are no mistakes in assembly or defective parts that will show themselves in the first few hundred miles. And also giving a new rider of a new bike the time to become accustomed to their new ride before going crazy and wiping out due to lack of familiarity.
So I still hold that the break-in recommended in the manuals is the right way. I also don't sweat it if those limits are slightly exceeded momentarily for a few miles. Ari didn't mention anything about warranty but that is likely because how you broke in your bike cannot be proven one way or the other. You're on your honor about that... except that IF a problem does show itself in the first few hundred miles and you left the dealer burning rubber for the next few hundred miles you only have yourself to blame for that... and wondering if taking it easy at first might have prevented that issue. Of course, if there is a defect that shows up in those first miles I totally agree with Ari that it would be far better to experience that at more conservative speeds than tearing down the super slab at break-neck speed... possibly resulting in breaking your neck. So we're back to: If it doesn't matter then being conservative won't hurt. And if it does matter then being conservative will be better.
There will be those who only listen or watch the first half of that video and ignore or take a pass about everything else.