Try reading the Sipjin explanation again, which states that hopefully he develops some assistants who can help him teach, which frees up his time for going back to training. Too many instructors fall into the trap that you talked about. That's why I think it is a bad idea for 1st Dans to start teaching or leading classes, because they get into a routine that does not allow for training.
But I think you are beginning to understand that within Kukki Taekwondo, there are all kinds of methods and everyone does it differently. I think you have this idea in your head about what is or isn't Kukki Taekwondo, based on what you see around you, but I think you need to let go of that to see it clearly. The empty your cup so you can taste my tea idea from Bruce Lee.
The fact of the matter is that Kukki Taekwondo is all over the spectrum, although I do see movement towards the Kukkiwon curriculum. Less than twenty years ago, you saw Chang Hon, Pyong Ahn, Palgwae, and Taeguek poomsae, as well as Moo Duk Kwan, ITF trimmed, and all kinds of other uniforms at our state championships. Today, we have most everyone doing the Taeguek poomsae, with the exception of one school, and everyone wears v necks.
The fact that you are here and are interested in ways outside of your own club tells me that you are different than perhaps some of your seniors. The 4th Dan who asks you for example, "What is Kukkiwon" obviously does not share the same sort of intellectual curiousity that you do. He is happy going to class, training and that's the end of it for him. Not you. In some ways your school is like the garden of eden, and you are like Adam eating fruit from the tree of knowledge.