I think many (but not all) domain experts end up that way because they are so interested in a topic, they've internalized all the jargon and assumptions required to get there. It takes quite a bit of effort (and practice!) to keep the viewpoint of the common person in mind as well.
Feynman loved explaining things, so he had to keep trying to explain them in a manner that the ordinary folk could understand, but he also loved physics, which kept him diving deeper, and playing with it.
Having charisma and knowing what people want, and how to sell was Steve Jobs portion of the game, once the initial technical hurdles were solved. Woz likes to minimize circuits and do clever things, that was his part of the game.
Here on HN, the balance seems to be keeping it focused enough on hacking technology, while still appealing to those who want to make money off of it in yacht loads.
It's all about balance between at least 2 domains.
My theory is that many domain experts haven’t needed to communicate with a lay audience in decades (if ever) and thus aren’t aware of their own baseline assumptions. Seems like a startup idea, maybe? Convert academic papers into comprehensible English. Two Minute Papers does this but it’s only for technology.
https://youtube.com/c/K%C3%A1rolyZsolnai
This probably applies to early Apple. Wozniak, while clearly a technical genius, needed Jobs’ communication and design skills to sell “personal computing” and make Apple a mass-market company.