Pyotr Kropotkin in _The Conquest of Bread_ writes the following conclusion about the advent of greenhouse agriculture and steam power and what they mean for European labor at the turn of the 20th century. It's a communist (well, they'd argue about that) book so it's got a lot of numbers and no great punchy pull quote, so this is as succinct as I can be:
> In basing the maintenance of these 150 acres on the Jersey average, requiring the work of three men per acre under glass—which makes less than 8,600 hours of work a year—it would need about 1,300,000 hours for the 150 acres. Fifty competent gardeners could give five hours a day to this work, and the rest would be simply done by people who, without being gardeners by profession, would soon learn how to use a spade, and to handle the plants. But this work would yield at least—we have seen it in a preceding chapter—all necessaries and articles of luxury in the way of fruit and vegetables for at least 40,000 or 50,000 people. Let us admit that among this number there are 13,500 adults, willing to work at the kitchen garden; then, each one would have to give 100 hours a year distributed over the whole year. These hours of work would become hours of recreation spent among friends and children in beautiful gardens, more beautiful probably than those of the legendary Semiramis.
> This is the balance sheet of the labour to be spent in order to be able to eat to satiety fruit which we are deprived of today, and to have vegetables in abundance, now so scrupulously rationed out by the housewife, when she has to reckon each half-penny which must go to enrich capitalists and
landowners.
The work week has gotten much shorter since this was written, no doubt about that. But we keep aiming for ~5 hours a week with the profits of our higher mechanized productivity spread out among everyone and somehow we keep missing that one.
> In basing the maintenance of these 150 acres on the Jersey average, requiring the work of three men per acre under glass—which makes less than 8,600 hours of work a year—it would need about 1,300,000 hours for the 150 acres. Fifty competent gardeners could give five hours a day to this work, and the rest would be simply done by people who, without being gardeners by profession, would soon learn how to use a spade, and to handle the plants. But this work would yield at least—we have seen it in a preceding chapter—all necessaries and articles of luxury in the way of fruit and vegetables for at least 40,000 or 50,000 people. Let us admit that among this number there are 13,500 adults, willing to work at the kitchen garden; then, each one would have to give 100 hours a year distributed over the whole year. These hours of work would become hours of recreation spent among friends and children in beautiful gardens, more beautiful probably than those of the legendary Semiramis.
> This is the balance sheet of the labour to be spent in order to be able to eat to satiety fruit which we are deprived of today, and to have vegetables in abundance, now so scrupulously rationed out by the housewife, when she has to reckon each half-penny which must go to enrich capitalists and landowners.
The work week has gotten much shorter since this was written, no doubt about that. But we keep aiming for ~5 hours a week with the profits of our higher mechanized productivity spread out among everyone and somehow we keep missing that one.