Your alternate theory is particularly interesting. We forget that in days gone by, technology spread with difficulty, and certain crafts had their knowledge par

Your alternate theory is particularly interesting. We forget that in days gone by, technology spread with difficulty, and certain crafts had their knowledge particularly well-hoarded. It's one thing to say "you make a longbow from a yew tree in this manner", and another to actually do it effectively. Even if you had a few people who knew technology X in the local population, they may not have wanted to share that knowledge for fear of diluting their own power and prestige, regardless of what Mr King wanted.