I'm not sure that modern analogues directly apply, espicially in relation to market economies. While certain spells may imply that such economies would form based on our cultural biases, I'm not sure that are biases are correct. First if we're going for believability, it's important to realize that in a typical D&D world, power and money are not as intertwined as they are in our world. It's also important in my opinion to consider that Arcanists and espicially Clerics, probably have more important concerns then making cash. Mostly, I'd try to keep their high level of personal power in mind. While some open selling of magic items would probably happen, it's hard for me to see anyone settling down for much longer than it takes to refill some neccesarry coffers in order to pursue some other agenda.
Alright let me refocus. Let's take Dernav for example. Dernav likes to spend his time finding new uses for his arcane talents. Dernav can teleport across the continent, launch flaming spheres out of his hands, and spy on his enemies using magic. Since Dernav is powerful, he has a good deal of enemies. While he needs money to conduct his arcane research, and conduct his political affairs, Dernav only has a need for so much money. He also realizes that the more magical equipment he sells in the open market the less impressive his abilities become in relation to everyone else's. Now when Dernav needs some money to support his cash fliow problems, he makes magic items for people. However, Dernav is careful about his customers, because Dernav has enemies. He needs to minimize his risks, since he prefers not to get a sword,bearing his own arcane mark, plunged into his rather fragile guts. He also realizes that open advertising draws attention to himself, so Dernav works through a number of associates because Dernav doesn't like the idea of his political goals being upset because he decided that selling goods with martial capability to any bum off the street witha few gold pieces was a good idea.
I do prefer to run games with more archaic economies; I do this mostly due to the way such systems tend to emphasize the dynamic of personal power vs. finincial power, which I think adds value to my games. I'm no history or economics expert, but I believe market level economies started to propitiate due to an over-all leveling of personal power.
With that said, this is a fanatasy roleplaying game. I don't think anyone will ever be able to introduce a believable fantasy world based on D&D's assumptions, but my interpretations have worked for me. They might or might not work for you. Good gaming either way.