Oh don't misunderstand; I understand economic forces are constant and the theories we use to describe them are what changes, much like how physics are constant and our theories to explain them are constantly refined. What I'm saying is that MMT has holes in it and cannot be the basis of the system, but can be a model players use to interact with that system. A player could run his dwarf economy through high rents and issued currency as a means of forcing dwarves to work, which is the core of MMT as I understand it. Or a player could run his economy through central command means, or through free markets...
Basically, if there were ever a game to simulate an economy and not merely pretend to have an economy, this is the game. We have every nail on every finger of a dwarf, lets have every economic nuance as well (in Dwarf Mode, at least).
I by contrast understand economics to be fundermentally unstable and ultimately determined by social/political systems (themselves determined by psychology/ideology). An economic system is built upon political assumptions about social/legal system and human nature. Economics thus does not really advance, it simply shifts depending upon the changing balance of political powers in an evolving political system.
Therefore the applicability of real-life economics to dwarf fortress is not there because there is so little similarity between the social/political system of dwarf fortress and that of real-life (except for ideal communism, which does not exist). If someone wants to advocate changing the economic system they must identify an economic problem in-game and proposing a solution rather than trying to apply real-world abstract economic theories to the game.
The problem is that there IS economy under a feudal system AND in Dwarf Fortress. Let's say you managed to gen a game where the goblins have been completely wiped out, and placed a fortress in the calmest biome you can imagine where the most dangerous enemy you face is a tantruming bunny (which would be completely the most functionally boring fortress ever, because there would be no fun). Further, let's assume that you managed to find the one location with no candy (oh dear God NO!).
Well, you have a limited amount of dirt on which to build farm plots. You could take the time to flood your fortress while burrowing everyone outside until the water drained out, but you would still be limited in how much farmland by the simple problem of space. We're going to assume that you want to have industries running. You'll also want to build bedrooms and dining halls. This is simply getting the basics of what you need to run a fortress. You'll need space for the plumbing if you want to do controlled flooding to flood portions of each floor for farming.
And now comes the history major in me. Even under a feudal-era, there were daily wages. Usually, the daily wage was its own denomination in the local monarch/count/duke/regent's currency. This was a process borrowed from biblical times when a day's wage was a Dinarius. So there was a minimum wage in effect. This wage was enforced by making specific markings to prevent people from filing down the sides of the coin to make counterfeits, as well as other methods to prevent false payments.
So, let's assume that, when the aristocrats show up or are appointed, they start a currency. Let's also assume that Toady wants to simulate a feudal economy. There would automatically be a market force called minimum wage. In addition, you add the forces of space scarcity, resource scarcity (no candy in your gen would mean that the only way to get candy items is through trade, which I have never seen happen), and labor scarcity. IF you get up to a thousand dwarves, that is a lot of workshops to manage (not to mention an FPS hog with all the pathing). Your manager could help with assigning the jobs, but you would definitely NEED a bookkeeper.
Now, DF has the added FUN of mandates. Let's say the Baron mandates the production of Red Spinel items (a la Headshoots). Now, you would need a jail if you didn't want to risk a hammering leading to a tantrum spiral because you have no red spinel to make stuff from. That is a market force that has nothing to do with politics and everything to do with supply. Supply is something you can't politicize no matter what you try.
Besides, half of the FUN of the game is that it is unpredictable. That is just like life. Politics DOES have an effect on economy. How your government is set up has a marked effect on your economy. Despotic countries have bad economies, while more modern pseudo-democracies have better economies. Feudal economy is its own monster and was, in reality, very much like the Roman economy without the Roman empire. It was marked with discrepancies in currencies that moneychangers were made necessary for.
Now, what I agree with you on is that economy SHOULD be optional. However, if we do economy, we have to do it right. I, for one, would love to have an economic system, mostly because I hate assigning the bedrooms individually.
What I am disagreeing on it whether or not it is an understandable force. This much is true: we can quantify and predict certain economic trends and forces. There are, still, others that are unpredictable. And that should be simulated in a DF economy.