Drearyweather says:
“No where do our publications state that the heavenly calling is due to Christ's incapability as a ruler.”
Yet the idea is hinted at when WT publications say stuff like this: Jehovah could have given angels as co-kings and co-priests along with Jesus, but He extended this privilege to humans because they are the one who are tried with Jesus on earth who gave a fitting reply to Satan’s taunt.