You say that armor prices are being driven down because you have 10+ people selling it...

That just didn't happen in FFXI. Crafting was tedious and dicy, because generally only HQ items were any good or the ones with rare NM drop ingredients.

What you're describing to me is still market factors that are not influenced by the method that players trade with each other. Items in FFXIV are extremely easy to obtain compared to the server population we have now, and with our top heavy userbase (meaning, almost everyone is at end game now), everyone is more or less farming the same items.

Take a look at low to mid level items. Prices are more stable there, and the items themselves are more profitable to farm in some cases.

Again, the way in which players trade with each other has nothing to do with price fluctuations and inflation/deflation.