With sufficient design iteration and manufacturing scale, there's no reason why a humanoid robot couldn't be cheaper to manufacture than a compact car. That's competitive with a single year of unskilled human labour — and that's before you account for the robot working 7 days a week, 18+ hours a day, for many years. No messing around with undocumented workers, no risk of unionising, no sexual harassment accusations, no training costs (after training the first robot), no worker injuries resulting in expensive litigation.