Why is the King weaker than the Queen?

You should read one of the many historical accounts of the development of the game.
There a was an excellent book on the subject "The Birth of the Chess Queen" by Marilyn Yalom. It details the story of the change starting 1000 years ago in the role of the original vizier advisor from one of the weakest pieces on the board to becoming the queen, certainly the strongest by 1475. The changes reflect changes in feudal European society, which saw the rise of powerful queens.

That's fine but threads often take on a life of their own.