The only thing keeping the value of armor in check in this game is the fact that much of it gets consumed via materia breaks. Otherwise even the highest level of crafted gear would be worthless...hell for the most part it still is until you get some good melds the actual creation of (Most) items does not net you money.

Market saturation would happen alot faster than you think. This isn't FFXI but we can all take lessons from what items did/didn't become worthless in the span of two weeks after it was released.