Why hasn't Middle Earth had an Industrial Revolution?
Something not mentioned in the article: Middle Earth is depopulated. Without large market, it does not make sense to produce at scale, nor you will have the capital to do it.The main characters travel hundreds of kilometers down the biggest river around and they don't encounter other vessels or a populated settlement until they reach Minas Tirith. And I'm not even mentioning the missing cities and villages in the inland part of the travel. We can say that this is due to lower birth rate in the numenorians who obviously have reproductive issues as mentioned in the books. Another reason is the brain, knowledge and capital drain caused by the large elvian immigration going for centuries. Dwarfs have the excuse of a long generation length to explain why they are not multiplying like rabbits for the thousands of years since the last world war, however, Tolkien does not provide a good reason for the other human nations, the orcs or even the hobbits.Possible explanation might be the unstable security situation on the continent, however, most of the societies are not described as being constantly under the risk of a raid from nearby orc. Aragorn is able to defend most of the north with a few hundred irregulars, while the east participated in only one war 60 years ago that was done in a few weeks time. The south is not described, but nothing unusual there as well as far as the books go.