And where there are opportunity costs, there are often bargaining arrangements to be made to reduce these costs. Enter the gold farmer.
A gold farmer will spend hours and hours and hours monotonously doing the same interminable task over and over and over again (like killing low-level mobs to collect leather) for conversion and sale to more traditional players in exchange for real-world currency.
The typical reaction to gold farming (from ordinary players) is a mixture of pity, contempt, and dismissive indifference. The margins on gold farming are razor-thin, which should be unsurprising given rumors of conscripted prison labor.
Is gold farming euvoluntary? One way to look at it is that (relatively) well-heeled players are exploiting poor "players" (you'll find that most non-casual players will adamantly refuse to consider gold farmers to be actual game players) to obtain game items without the toil expended by honest players. It's almost a double offense: not only do the dilettantes get gear they didn't have to grind for, but they did it by taking advantage of poor Chinese (or so goes the stereotype) workers clicking away in 18-hour shifts in rooms full of computer banks and notably devoid of air conditioning. Again, so the stereotype goes. BATNA disparity. What's more, people buying gear from gold farmers fail to develop the skills needed to play the game properly in some of the more challenging areas. In another context, they'd be called "poseurs."
But the same economic analysis that applies to sweatshops should apply to gold farming as well. People turn to gold farming because it's the best option among the competing alternatives. Even in the prison situation, it's probably better to click a mouse button than to spend that time turning big rocks into little pebbles. And for the faux gear-hungry secondary market shoppers? A n00b is a n00b, even with +5 devout greaves or whatever. If you find yourself galled by someone who simply paid cash for the best gear in the game, consider carefully exactly what aspect of that makes your gameplay less enjoyable. If you find that your answer lands somewhere near "envy," you might be faced with an opportunity to work on your ethical development.
The same goes for developers. There might be some legitimate reasons to regulate (or even eliminate) secondary markets, like PvP balance or whatever, but if high moral dudgeon starts to creep in, please consider carefully what alternatives you might be subjecting suddenly-unemployed gold farmers to.