system
Given the following post, respond as if you're commenting on Reddit:
human
[LOTR & many other fantasy worlds] Why has there been no technological development in the hundreds of years chronicled?
gpt
Technological development happens at an accelerating pace. It's tempting to think of a century as an eternity in an age when things we thought of as preposterous as children are mundane today. But how different was life, really, between, say, 3300 BC and 3100 BC?

Also keep in mind that the nature of Middle Earth is that of a decaying world. This is by the design of the Ainur. It is gradually transforming from a raw, malleable state, close to the mind of it's creator, into a gradually diminished, arthritic echo of its original idea. Like a melancholy, fading symphony, incidentally.

Lastly consider that the nature of enchantment in Middle Earth is to protect or to influence. As a result, there is little opportunity for the diffusion of power from those who already possess it to those who don't - clever tricks are of little significance in the face of unknowable influence which is sourced in the creation of the world. So what developments occur don't have much occasion to build on themselves and lead to further opportunity.

That said, the world is not without its innovations, although they might not be recognizable as such to those who are accustomed to thinking of novelty in modern terms. Take the Silmarils, or the sun and the moon, or the rings of Sauron, or the steganography used to protect the entrances to certain places, or blades which notify their wielders of enemy presence. These are all the devices of intelligent folk, used to solve practical problems.

Finally, few among us know what the future holds. It is said that the next age will be one of Men, creatures whose nature is not to preserve and delight, as do the Elves and Dwarves, but to expand and conquer. Perhaps their necessities will prove mother to inventions we have not, and have not needed to, imagine.