Nah. Iwao gave it his all and was simply outclassed by Lan Di. 46 is not that old either Lan Di was also in his 30s so not in his physical prime either. If Iwao knew the move he would have been able to counter it. Besides the move can’t be pivotal to the story since the scroll is missable in S1.
31 is doing OCEAN's better than 46, especially as Lifer martial artists. You commonly see people still compete at that age in Combat Sports. You're gonna have a hard time of it finding competitive fighters at 46 (Bernard Hopkins and Randy Coutore being huge unicorns). Not only the physical nature of competing in Martial Arts, but also most people naturally just want to start relaxing a bit.
For example. I checked every UFC Champ (Man & Woman). All, except Sean O'malley are older than 30 years old, and O'malley is 29. Jon Jones & Alex Pereira are the oldest at 36. You might not be as nimble, and recover as quickly as a 21 year old young man in your 30s, but a lot of the time you end up combining the knowledge you've gained over that time, so you're probably a smarter fighter than your 21 year old self in terms of how you train, how you approach a fight, and the amount of situations you've been in while competing.
Lan-Di presumably lives a life where he's constantly in danger, and has to stay physically & mentally sharp at all times. Iwao is older, and by comparison lives a peaceful existence. So yeah I dont disagree that Iwao got picked apart. Simply stating, there's not much he could've done, when he also has to focus on protecting his son, against a much more fit opponent. If he had fought to the death, it probably would've been a long time ago from that day. How do you just turn that switch on that you have to suddenly fight to the death, after chilling out with your family, doing boring daily chores or what have you, when Lan-DI KNOWS what he's gonna do, prolly been training his ass off for that moment for God knows how long. Meanwhile Iwao doesn't know he's about to be surprise attacked with an opponent willing to fight to death. Or maybe he had a vague idea that thing's could get dangerous, since he did go through the trouble of hiding the mirrors, but he still seemed shocked it was Zhao's son there to kill him. How do we even know if he ever found a counter for that move, or if he even learned how to use that move himself? There's so much stuff that hasn't been explained. Its fun theory craft, but at the end of the day probably not worth thinking too hard about it.
What do you define as "pivotal"? I'm not saying the scroll is gonna be something integral to rounding out the plot, but as an aside it would be nice to have it explained, and if it somehow turned out that it was the move Lan-Di used that would be pretty cool. Shenmue 1 was a LONG time ago, obviously a lot of plans have shifted since then. In 2+ decades Suzuki could've had the initial idea, and decided he wants to flesh it out to be something more than optional content. He's not beholden to sticking completely to a script he wrote ages ago, especially when no one has any idea what that move even looks like. If anything that's why I trust that there's gonna be some kind of worthwhile pay off to the story of the scroll.
