Prices keep increasing because more players are reaching higher levels and obtaining higher amounts of gold. It's basic inflation for the start of a game, eventually it will balance out. What i'm trying to say is, the reason the prices are raising is because people can afford it.
But to put it simply, selling items is not a "Gold Generating" mechanic. It is only moving around the current gold that player's have collected. Like your post says, if everyone only traded then there would be no income to manage it. Though, I think the gold generation is fine for the moment now that they adjusted the World Boss Drop Tables. It's not like gold is suppose to be easy to obtain, it's the highest form of currency. Most things in NPC markets only cost copper, so it would be reasonable to say that silver is suppose to be the most used form of currency. Gold is more like having a $1000 bill... even if you see those +13 purple items going up for 3k-5k gold.
It seems that the income/economy systems were well developed. Crafting and Trading offers the highest gold yield at the moment, but lacks the ability to generate it. Hunting/Raid parties can use the party buffs to obtain more gold and resources from farming mobs and world bosses but lack the time to focus on crafting. Then Wyverns and and Repair Blacksmiths offer an outlet for the increasing market. Hunting parties rely on the crafters for gear and resources, and the crafters rely on the hunting parties for gold. Everyone eventually uses the Wyverns or Blacksmiths, but since the gold hasn't properly dispersed through the market yet it's not being removed fast enough. Eventually the market will stabilize when more people reach endgame and stay there. That being said, when the new races and classes come out... the economy will most likely drop for a bit again since many people will go and make new characters without the crafting experience or combat abilities
Thanks for your oppinion, so far the support for the post is 98/100% 
