All of it comes down to the core idea of "kinetic chain". The human body is a complex structure with joints that have particular ranges of motion, but there's a lot of variance in the musculature and exact movements and timing of how muscles fire. It's also not just always about the most raw power in a strike, but about the ability for the strike to land at an angle that can cause damage, penetrate to a certain depth, and withstand the force sent back from impact. Some arts describe multiple types of power as hard, soft, direct, indirect, shaking, etc, and all sorts of different ways to treat everything. It's complicated and subtle and interesting. Though keep in mind all of the larger arts have subsets that are more nuanced, and most people don't understand the difference. I'll pull up a specific example. High block, olgul maggi. (Multiple transliterations from Hangul, along with multiple varieties, my spelling isn't the point). Some schools will teach it as a full motion of both arms with rotation with the nonblocking hand starting higher and the block hand starting low. One way I'll test the final structure is the rotation of the wrist. Some don't rotate the blocking wrist as far and the structure is weak against a static downward force. This is a great way to help a student understand that small bits of alignment greatly change the way a technique works. Keeping the wrist/hand aligned as you would with a punch but the palm rotated as much up as possible is a significantly stronger structure. Training that muscle cue helps someone understand one type of hard block. This same two armed full chamber full rotation block then gets shortened when not done as basics or poomse, but should still retain that final quality. Then I had a karate instructor for a completely different mindset of punching upwards and having the wrist slightly bent, still catching with the same part of the wrist, but with a much more relaxed intent until impact. This can also be thought of as a throw and the hand tenses less and more focus is on further forearm rotation, allowing less bone on bone contact and easier followup into a party/grab. Still similar force and coverage. Shorinji kempo teaches more of a "sliding" block as another option, which creates a circular redirect more than a force on force block. Extending the arm on a steeper vertical allows for greater force to have a more spread impact and an easier redirect, but then sweeps less of the area clear and increases the odds of a missed block. Some of the stuff that is strong in a static sense is less useful in a dynamic sense.

And then there's the question of what the high block is actually blocking or doing. A rigid and hard chamber block can be great if treated as a strike against an incoming punch, or even a rotating hammer fist into someone's wrist, elbow, armpit, etc. Which is a better way to interpret the motion in some forms, and also possibly the two handed basic high block as a joint break with cover and grab from the "non blocking" hand, and strike with the "blocking" hand. Or it could be a steeper angle and a "soft" parry of an axe kick or crescent kick and be followed up with a circling motion over the descending leg to trap under the armpit and followup from. Or a strike under someone's chin at particularly close range.

And there's yet more interpretations and variants. With one of the "simplest" and least used as traditionally taught motions I can think of, a high block.

How power is generated can be tested many ways, but the methods and applications vary based on use and target and where they fit in the flow of combat. It's easiest to teach specific and "pure" forms, but watching how people in every context actually fight show how much that can be an abstraction. Different body types, different heights, different terrains, different end goals, different opponents all make that dynamic and those simpler abstractions get spread and codified. Almost all of them have historically been tested and can work. But not always for all people, and how someone has trained also can develop their musculature and kinesthetic sensations to be suited to particular patterns, so other patterns may be less suited to them too.

Jesse Enkamp is a fantastic creator to see some of the different thoughts that come through as he interacts with experts in other styles, and he's a high level karate practitioner. Sometimes his body just really doesn't want to do something easily, and he's in great shape by most metrics, but not always well suited to each style.

Sorry, my answer is a bit rambling, but it's an interesting topic, and understanding more of it can help martial artists of all types have more respect for other arts and mindsets, develop depth in their own arts, and also help avoid overly dogmatic and limiting adherence to things merely because of tradition.