We manipulate the economy in this game. We manipulate the end results, not the process.
In a game there are two main ways to manipulate the economy. Either increase the amount of resources and the means of production along with job growth to support the increased activity. In other words, Sim City or one of the RTS types of games. However, even then, the net effect of improving the economy is people have more money to spend or resources to use. The problem with manipulating the resources and conditions is that is quite complicated and is a game in and of itself. Some RTS games have moved from this aspect just because it can get so tedious and complex.
In this game, we get a better economy by just investing in the shops. This gets us around the mechanics of riding herd on the factors that go into an economic system. Which can be fun, but is not a core part of the TES experience. Shops have more money to spend, which is what you would expect in an area with an improved economy. So, we can manipulate the economy in this game. We can also get the shop keepers to do different types of business than they would normally do, another sign of a better economy. Businesses expand when economic conditions improve or are expected to improve, again, we manipulate the economy.
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.
Perhaps more importantly, there are already many games for business and economic training. They are not mass market games, but they certainly can and do exist, and mass market games could certainly offer such features (just as America's Army games are based on more complex combat simulations used for US military training).
There's also the simple fact that EVE Online hired a professor of economics to supervise and maintain the game's economy so that it works in a realistic fashion. Obviously, a company that cares about offering a realistic or semi-realistic socioeconomic system does proper research and hires proper people to be part of the creative effort. The same thing is true for including various social issues (Bioware is quite explicit in their content, and Beth chooses to be more implicit, but both could use input from scholars in certain fields of academic study).