Let me start by saying - Technology matters, and in fact it is required to allow adventuring. Kind of a bold statement, but let me explain ...
It is pretty obvious by now that I love knowing how economies work in fantasy games. I wrote Grain Into Gold, and it remains our best-selling product on the internet. But knowing how the money moves is only a small part of the issue. I think you need to have an understanding of the technological capabilities of your various cultures and races, or you don’t know what’s possible.
In my research, I’ve discovered the differences between a bloomery and a blast furnace. Bloomeries are (in an overly simplistic manner) kilns that smelt iron out of iron ore. But what’s really important is that they do not liquefy the iron. Those pictures in your head of a smelting factory where they are pouring molten iron or steel, that’s a blast furnace. A bloomery produces “sponge iron” which needs to be worked extensively in order to produce useful iron or steel. But bloomeries were in use in some areas through the 16th century.
Blast furnaces on the other hand were able to actually melt the metal, which could then be poured into molds to make pig iron or other shaped products. The short answer on this is: Making a sword blade out of a bar of steel is vastly easier than making it out of a ball of sponge iron. How much easier? Well, I don’t think you can even consider steel armors without a blast furnace. Not even chain mail. Blast furnaces could be found rarely in the 15th century, but mainly came into their own during the 16th. So what am I saying? Well, if you have a game set in (or in the equivalent) of 1425AD, you should make metal armor incredibly expensive!
I assume the following: Every major city will have access to iron and steel smelted in a blast furnace and therefore access to “iron bars”. Further, the dwarves are producing various sizes of sheet metal and metal wire. Want to craft chain mail? It is vastly better to purchase steel wire from the dwarves (even after paying to have it transported) then to have someone pull the wire by hand. Without a blast furnace, I don’t think you see anything like plate mail, plate armor or even a great helm. Certainly not on someone without a noble landholding and the wealth it brings.
So I like to tie these things back into the game for all the gold farmers out there who think that things like this don’t matter to them. Well, without blast furnaces, I just took away your best armor types, and probably metal shields. Assuming that something like this existed, it would be incredibly expensive. If your game has specialized metals (adamant, mithril, etc.), yeah throw those out the window!
OK, so we’ve probably established that your game worlds need blast furnaces - Does that matter? Well, yes! The Earth ones relied on water power to power the bellows. Some kid on the bellows probably doesn’t work here - but does work for a bloomery. So you either put your smelter (or foundry) right next to a river, or you come up with some “magical” reason that they have other power. But iron ores are not typically found next to rivers, so the ores and the fuels are likely being transported on the river. So now you have established a trade route, and trade routes need to be protected from bandits. OK, few bandits are going to steal iron ore, but they would probably steal the pig iron.
This is the stuff we’re hoping to do: Help you figure out your world - here the technology. Help you build out things because they make sense, like shipping iron ore from the mine to the smelter by river barge. And help you with the adventuring parts too - such as the city’s armorer cannot craft or repair armor for the party because river pirates have caused a problem on the river. That should motivate most adventurers to get off their butts and go adventuring, shouldn’t it?