I understand, and correct me if I am wrong, that there is no automated "market" that balances prices at NPCs, right? All this inflation and deflation is generated then by dev's financial engineering, what surely has the defect of over- or under-reacting and specially reacting always too late.
My impression now is that nearly nobody mines (because it's become a too tiresome work for the produce) and that might mean that players do not have enough trias in their pockets (specially as training is so expensive), so they can afford less "luxuries" like good weapons and such, detracting from the profit of artisans.
Low base incomes is, as far as I can see, not good for crafters, who have to lower prices maybe, nor for gameplay, as training is heavily limited by its proportionally higher cost.
I understand that a game and virtual economy like this one needs sufficiently good basic incomes, that allow normal players (lowbies, midbies) to spend comfortably for their needs without excessive work (they are players after all, not real life workers who need a salary not to starve or go into mendicity). I understand that there must be some balance too but it's surely better for the system to be somewhat generous than the opposite.
Ideally I'd suggest an automated market engine, that would compute all transactions and be fine-tuned to keep an optimal economy based on real-time (or almost) adjustments between prices and basic productivity. Private transactions should also account though this may be highly impractical to implement, so guess that using NPC market evaluation would be a proxy decent enough, at least for precious metals.
This, as I say is just a suggestion for hypothetical development.
But another thing to balance the economy should be to fine-tune the availability of minerals and other items of some value (some skins?, what else?). Why are gold and diamonds so expensive? Because they are rare and you have to strive to find any. Why is iron cheap? Because it's one of the most common ores of Earth. So you should be able to dig and sell iron at a speed maybe 10 or even 100 times and at almost any location.
This natural correlation does not exist in PS but seems to be central to the value of things, at least at the simplified fraction of raw materials. Doing basic jobs as iron mining should be minimally profitable (easy access mine, geting an ore per try even at lowest levels...), reasonably decent price that pays for the work, if nothing else. Nobody is going to do a job that does not pay, not if they can just sit at a virtual tavern driking virtual beer that costs nothing instead...
Instead gold (or diamonds, or platinum when it existed) are almost not harder to get than iron. And they should be, however in a well pondered system.
The key piece is the producer-consumer, the working class, so to say. What does need one from real life? Food, clothes, shelter and some caprices, including leisure time. What does a PS citizen need? Training, armor, weapons... tools and materials if (s)he is an artisan. However nothing of all that is strictly necessary to play, so they are more in the sector of "caprices". For this reason you need some "welfare state": you need that people finds their way into the basic layer of the economy easily and without too much effort. They should be able to afford several hours of questing, training, maintaining weapons, etc. with not more than half hour of work at the mine. Roughly speaking but that's how it is: they economy will only flower if there is enough purchasing base, which is not to different to the virtual GDP.
Not sure if it helps or if it's clear enough but I needed to say this.