Perhaps it’s better to say that I don’t find teaching it any more difficult than say, explaining the rules of American football, which are probably even more arcane at the fringes, and yet millions watch it every weekend without much of a thought for how many rules they don’t actually know, and how often it doesn’t matter in the big picture.
Eh...
I understand the analogy you are trying to make, but I would say that the primary similarity between D&D and the NFL is that both of them are used by Derek as an excuse to raid my liquor cabinet.
DEREK!!!!
Again, I teach teens to play D&D regularly. It's not rocket science, but it's harder than people say. If a person is enthusiastic, that goes a long way. But even then- there are those who want to understand the rules, and there are those (the greater amount, IME) that are playing their Champion through level 7 and suddenly ask, "What is action surge, anyway? I have it on the character sheet."
I would go back to my original point- onboarding new players isn't hard, because 5e is forgiving, and because the group and DM will help them. And perhaps most importantly because you don't need system or rules mastery to have fun.
Kinda like being a NY Jets fan, I guess. Except that is never fun.