This is not quite accurate. For one thing, we don't have the ability to manipulate the economy so that it is anywhere near workable short of massive modding efforts such as Living Economy in Oblivion or the many, many mods that fix the completely broken pricing system for resources.
Living economies is just a tweak on the merchants, but it is not really a mod that effects the economic system of the game.
There could be more built into the game with regards to the economy. However, at what point does this stop being an RPG and start being a Simulation? Also, economies are rather complex things and to incorporate these aspects into a game that is not a Simulation starts to blur the line between playing an RPG and running an Economic System.
I have used mods that have Economies in them, where you have to feed resources into the mod, take care of labor and determine production. Sure, they were fun mods, but I found them counter to playing the game as I had to tend to the mods rather than play the game. I would removed them from my game after a while.
I would rather have a simplistic economy in a game where the economy is not the goal of the game. This game gives me methods to effect the economy if I so chose to, and this is enough for this format. If I want to play with the economy, I load up a Simulation game where I can really get into manipulation of Supply, Demand, and Resources.