This is no small thing: look at the pace of industrialization between the fall of Rome and the enlightenment? It was marginal, at best. But once the Enlightenment hits, and democracy starts to take hold, holy cow, things took off. That's a function of a lot of things, but it includes the dramatic change in politics and its associated power. This has always fascinated me so I want to address it:
When I was at Ohio State I took a class called Economic History of the World. The professor was a world-renowned expert in studying wealth by measuring height. He and a Harvard Professor had collaborated on this to study all the way back to the Roman Empire days. They were able to find sufficient records to do this because militaries usually measure all their new recruits so they had decent male height figures dating back centuries and even millennia because the Romans had measured all their conscripts and they were able to locate some of this data.
Anyway, your point that industrialization was slow from the fall of Rome to the enlightenment actually understates it. Citizens of Roman Britain were actually WEALTHIER than British citizens until about the last 500 years.
Basically all humans lived at or near subsistence from the dawn of time until the enlightenment. There were some mini-peaks: The Roman and Egyptian Empires were a good bit above subsistence but nowhere near where modern Western Societies are and it didn't last.
With the Egyptians, his reference was the Pyramids. Basically the theory he was working off was that any society wealthy enough to spend the resources necessary to build the Pyramids had to be a good bit above subsistence. Someone in class then pointed out that the Egyptians and Romans both had slaves. The Professor answered that while slavery is obviously a big deal on a micro level, on a macro level if your society is at or near subsistence then the issue of whether your laborers are paid enough that they can buy food or enslaved and fed makes no difference. Either way one laborer is one mouth to feed.
Two final points that I find fascinating:
First, both the Romans (~2,000 years ago) and the Egyptians (~5,000 years ago) were THISCLOSE to the Industrial Revolution. The Egyptians had a "Palace Toy" that was a kettle with a vented release. The kettle was filled with water and put over a fire. The release was vented such that as the water in the kettle boiled the steam releasing through the vents caused the release to spin. That is literally a rudimentary steam engine. If you stick a pulley on that thing the Industrial Revolution is on but apparently nobody in Egypt thought of that. Apparently they were too busy walking like this:
VIDEO https://youtu.be/Cv6tuzHUuuk?si=GPL6usYfpWUJP5IF The Romans were equally close. Middle class Roman citizens had whole-house heat. They had a boiler in the basement and the steam was directed through piping to the rest of the house to heat it. If you understand steam well enough to do that, you know enough to build a steam engine. I saw a comment in a history book once that while middle class citizens of Roman Britain had central heat, once Rome fell nobody in England, not even the King had central heat for more than a THOUSAND years. So yeah, the dark ages weren't just lack of progress, they were a substantial regression from Roman times.
Second, one of the primary catalysts for the Industrial Revolution was that the British ran low on wood. Humans had known for centuries that you could find black rocks underground (coal) that burned but as long as they had plenty of trees it was simply easier to chop down a tree than dig a coal mine. The English ran low on trees because they had used them all for ships, housing, and fuel so they started using coal. That helped set off the industrial revolution in several ways:
With a coal fire you can reliably make steel. Previously blacksmiths TRIED with wood fires but it was hit-or-miss and more art than science so they'd try and if they got Iron they'd make plows but if they got lucky and got steel they'd make swords. This is an oversimplification but generally how it worked. The English Coal Miners needed to pump water out of their mines and the first steam engines were used for exactly that purpose.