The obvious answer is: time period. Most fantasy is written in a pseudo-medieval period with significant resemblance to medieval Europe with exceptional variations (the inclusion of magic, fantastic creatures, and different locales). Since capitalism did not exist in such periods, it makes sense that such places would not be run by capitalist structures. To be fair, medieval Europe was not capitalist primarily because of two factors (at least as I understand it): slow transportation and medieval feudalism. It’s difficult to imagine an economic system like capitalism functioning in a place that is not only seemingly run by an authoritarian figure whose personal rules stand for the word of God (more or less), but also incapable of supporting a system that needs to change, adapt, and move at a rapid pace. Fantasy, thus, enacts this real-world lack; capitalism does not exist there because, as in our world, it cannot.
But why not? With magic such a prevalent force in many fantasies, why wouldn’t we see more of the capitalist structures that made up early capitalist America (or Britain, for that matter)? Magic lends itself so well to being a commodity, for good or bad. You can look to some of the strongest examples of late in which a market is given shape, and yet nothing in that shape indicates any sort of logical economic type. Harry Potter, for example, has Diagon Alley, and Gringott’s Bank, but yet we hear nothing of wages. We’re told there are rich and poor families, but it seems that the richest families embody the nobility and the poorest seem, more or less, like peasants. All of this is on purpose, I suppose, because capitalism is not a central theme, or even a side theme; capitalism is not important to Harry Potter. But why shouldn’t it be? Why does fantasy have to ignore these significant social issues in exchange for the adventures and prophecies (not all fantasy does this, but the stereotype of the genre is not unfounded).
I suppose what I’m asking is: where are my capitalist fantasies? Double entendres are clever!