Scarcity of necessities (be they required or perceived) creates the pressure that brings conflict to any population.

Yes. It brings pressure to change the situation so that the pressure is relieved; a sheppherd moves his flock to greener pastures. A hunter kills all the local mob spawns, and moves on to somewhere the cooldowns have already reset.

But also Scarcity of a thing is inherently an expense, an indirect cost, a thing that therefore makes the item less valueable. Difficult and Time-Consuming are expenses. They are not something that a player wants, they are a negative utility.

Replacing gold with salt? That makes little sense for troop production for example. Its much too specialized for a game of 3 resources only.

It was primarily a joke, but it is often posited that Roman soldiers were paid in salt...

Well, it was pretty valuable before fridges since it was the only way to conserve food (and it was quite hard to get, too).

Before modern refrigerators, they had what's called an Ice House. It was a big business bringing ice down from the mountains and storing it between hay in deep cool cellars. 7-11 started out as a chain of ice houses, until the electric refrigerator took down that industry. Does it seem likely there were a lot of people who didn't want the refrigerator to become popular? Even today sorbet has the lingering aftertaste of expensive and high-class, because it was made from the hard-to-get-at clean bottom ice from the ice houses.

If pressure is relieved by cooldowns or the resource can be accessed anywhere then the resource isn't scarce. It's plentiful. Scarcity indicates the limit of quantity or access. If a player has plenty of quantity of a needed resources local mobs, wood, popularity, etc it isn't scarce. A resource in demand that is scarce makes it more valuable and only less demand can make it less valuable (though why you'd have something on a market that isn't in demand baffles me, specially a game market).

"Difficulty" is only a negative utility if there is no way to learn to overcome that difficulty, and if "time consuming" is negative you should tell that to players that have sunk literally years of their life of cumulative hours into video games. Time consuming only sucks if the player isn't having fun or being challenged.

Gotta say I disagree with almost everything you've said.

• Cooldowns directly control scarcity; lengthening the cooldown on a unique mob drop reduces the number of that item in the game universe.
• A desired resource that is scarce is not more valuable due to it's rarity, it is only more expensive. That is to say, an increased cost.
• Difficulty in acquiring a resource is a cost payment. Easily acquired resources are less outlay to acquire.
• Time consumption to acquire a resource is also an expense paid. Sooner is cheaper, later is more expensive.

A scarce resource is more valuable since the quantity does not meet the demand. The pressure to hold a scarce resource creates conflict.

If there is demand for a scarce resource (more demand than supply), then competition can drive the price up. Traditional Economics suggests that demand will go down (some people just can't/won't afford the new price) until supply and demand settle on a price somewhere in the middle. Not everyone agrees with the Traditional Economics models though.

But price and value are not the same thing. For example, in a game where citizens require food to live, food has value. And yet no price has been assigned.

The reverse is also true, a thing with an assigned higher price can have no additional value. In the MMO game Age of Conan, players can buy arrows that range in price from extremely cheap to astonishingly expensive. But the difference in arrows provides no contribution to combat. My guess is if that game had open markets of trade between players, the price arrows would probably gather near the same price for all types of arrows.

I'de like to address the two point in reverse order. Second point first, the price of arrows in Age of Conan is not up to players; arrows are sold by vendors at a specific price for a specific type. And they have no combat difference; the damage output of a player is unaffected by the quality of the arrow. First point second, there is an objective difference in wealth between the citizens of the USA and the citizens of most of Africa. It's quite real, not some subjective interpretation, or theoretical hyperbolie. But price is astonishingly flexible, and seems to be run mostly by marketing and PR. Is a 56" TV really worth hundreds more than a 36" TV?

On the topic of theories and models, one of the more interesting ones has to do with the explosion of options available to the consumer. The number of things we trade is skyrocketing. We could then measure wealth in Stock Keeping Units (SKU), and say in the general sense, a wealthier nation has more options, more things to exchange, more choices available. The end-game of this line of thinking is that the creation of value is the additional knowledge. For more on this line of inquiry, see Origin of Wealth, by Eric Beinhocker.

Speaking of Africa and the Wealth of Nations...Here's an observation: Why is it that the cradle of civilization, the oldest societies ever to exist, are also the most backward of nations? Why are they not the most advanced, having had the most time to develop? I have an inkling of an idea that maybe societies don't develop on an endless timeline of advancement; maybe there is some sort of birth and rise to adulthood, a flowering to maturity, a time capsule stamped with the technology of the time in which they were born.

A similie is businesses that rise and replace each other in a similar fashion, with new developments not so much spread across everyone as being brought into play by a newcomer. And this brings us full circle back to video games, because one of my pet peeves has to do with the way 4x space colonization games develop over the course of a single game. They start as a race that is almost immediately decided by whomever takes the initial lead. The remainder of the game is just the biggest fish getting bigger. You never see the fall of IBM from the PC market, when upstarts like Dell and Apple take to the scene. You only see Wal-Mart ruling the galaxy.

I'de really like a model that provides a way to generate not only the rise of empires, but the rise of new empires which supplant the old.