You had to level a craft to near-max in FFXI not because of the Auction House, but because of how stupid the market was set up. Items you synthed to level up your crafts were near-worthless and could not be used for anything, and you either vendored them or tossed them out.

Then when you got to high level, NQ items were worthless as well, because everyone and his grandmother was doing the same "profit" recipe, and the market became oversaturated with NQ items. HQ became the only profit.

If you want a healthy economy, you have to make sure the items people create leave the economy at about the same rate that they make them.