So, there is another aspect to this issue that the author of the cited article touches on briefly but then does not revisit, and that is labor.

It's funny because he starts getting into that with his high-level discussion of the Roman economy, as an essentially alien thing, but then almost makes the same mistake as the "old modernists."

Yes, everything he describes connects the dots in terms of establishing the basis for the industrial revolution. But he doesn't include the labor factor. The ur-question behind all of the technical innovation that drove the Industrial Revolution -- and indeed its underpinnings in the mechanical power generation of the pre-industrial era -- is: why not just get lots of people to do the work?

Like... why were there so many water-wheels and windmills to begin with? Why so much animal muscle power for that matter?

Like I say, he mentions this question but then shies away from it, which is a little surprising. Because one of the glaring differences between Great Britain and Ancient Rome is that Ancient Rome didn't have a manpower shortage. If you needed 20 people to pump something, or even if you needed 200, or 2000, you could get them. Or to turn a wheel. Or perform any repetitive work that we would today associate with a machine.

We have become accustomed to not thinking of 17th and 18th century Britain in those terms, as a labor-scarce society, because we look at the energy economics of work in that milieu and we say, "Oh well they had labor enough, and oh look at all these machines they also had, everyone has machines, that's just a normal thing to want in any society." But that belies the issue. These are not independent phenomena. The machines existed precisely in order that the economy do enough work while still having enough labor. And that goes back into the proto-industrial era of the early 18th century.

By the time the steam engine comes along, the stage is already set. Yes, of course the steam engine was valuable for pumping water from coal mines because the labor requirements were prohibitive. But why? It's because Great Britain didn't have a large class of idlers, fed by patrons to hang around and be available for labor-intensive tasks. And, increasingly, Britain also didn't have slaves. Certainly not a large slave underclass the way Rome did.