I was thinking of coercion in the sense of, normally market actors are also vulnerable humans, who need various things from their communities to survive, and if you don't behave in certain ways (selling your labour, etc) you cease to get those things.

In Diablo, you can be a pretty rational economic actor, because there isn't this impinging plane of crushing material need distorting all your decisions. As such, it's not necessarily a good model for understanding real world economic behaviour.