Recently, I wrote about treadle pumps that let human power replace diesel power for irrigation. As a one-to-one replacement it sounded pretty oppressive. But it turns out that it is not a one-to-one replacement.
Poor farmers who only earn a dollar or so, per person per day, can afford to do a lot more irrigation with treadles than they can renting diesel pumps from rich farmers and buying diesel fuel to run it. So they multiply the size of their harvests by two or three, their incomes by even more. Even in a formal efficiency analysis, you are probably increasing rather than decreasing the output per unit of labor. In human terms, you are increasing the amount of fresh vegetables the family can eat, and paying for things like school fees in areas where education is not necessarily completely tax-paid. So you are making life better for the farmers, and even slightly increasing their autonomy from richer neighbors.
