I beg to differ, Bricklayer B would reject the job on account of being too busy doing work that paid a sum reflecting the value provided rather than reflecting the sociopathy of the employer.

Or.. B demands a higher payout. That reduces his customer base without affecting his revenue significantly. With fewer customers he has more free time on his hands, in which he invents robots that build brick walls. He now lowers his hourly rate.

Of course; otherwise he would be punishing himself for his efficiency.