You play the hand you're dealt, or you get out of the game. Getting out of the game is always an option, of course. But you don't always have the ability to choose or change your cards.
You’re the one who dealt the cards! You’re the alleged (self-described) manager here. No wonder you got pushed around by somebody who was able to do their work. You seem to see yourself as the victim of circumstance rather than in control of anything.
They should probably have promoted the guy who was reading the book. 0% chance he'd let one of his reports make him do work that the report should've been doing themselves.