Exactly, they have absolute control over the drop rate, thus the auction house economy.
If Blizzard released this game with zero cash economy (game points only) then I'd have no squabbles. Really, it's nothing to do with Blizzard or the genre.
The in game auction house is restricted by the amount of in game gold you get. Which is restricted by the programmers (the progression limit). So, they can try to lengthen and stretch out the time needed to get a sword or whatever in game. However, paying cash you can get it instantly. Now, translate that to any other game. Say football. Want more goals? Well, normally you have to play, but you can pay to get early goals. How about poker? Well, normally you have to get a good hand, but now you can buy Aces.
In single player games it does not matter if you get an advantage (it's single player) but at the same time, there is no value to buying extra goals or Aces. Your the only one player, so can just skip ahead (say in solitaire or minesweeper).
Only if you add restricted collectibles into a game do you encourage underhanded ways. Achievements in Steam = in game points only. So, if someone swaps a game save for achievements, nothing happens. Can someone charge and sell these on Ebay? No, because the distribution is unlimited, no one can charge for them. Same goes for old Mario or Sonic saves if you want to "get all the stars" or "get all the rings" or something. You can just swap saves. But, if you make those in game items restricted or cash exchangeable, you add the risk. So, to me both Valve and Blizzard can remove the risk, but for the chance of profit, they do not.
So they can remove the risk, but it requires them to sell a game and give the players the control or give the players full content with the purchase. They do not want to do this, and this causes the out of game trading. Adding an in game auction house does not solve this problem, it only moves it from Ebay to the games version.
You need to ask, "why is someone willing
to pay to progress faster in a game"? I do not know of any physical games where this is allowed (rowing? Football? Tennis?). I know of very few paper based games it is allowed (not allowed in cards, monopoly, scrabble). Only the likes of WH:40k and Pokemon are cash trades ok. At least there we have physical items that have some worth. What if all the WH:40k and Pokemon cards were photocopies, then what are they worth? Here a game (not just D3, there are others on the market too, like TF2) has presented a stat booster and charge for it.
Just to make it totally clear, I am against paying to "progress faster" in a
digital game. Why? Because it's digital, the speed of progression is a single command, something that is values at such a low price. Something like "speed =10" or "attack = 100". It's like trying to charge for the ability to turn pages in a digital book faster!
PS, I just remembered, even in WH:40k there is no rule against a player making an entire army out of their own makings. No purchase nessisary as long as you keep to the rule book. You cannot do that here. I ask why? The answer would be very interesting.
Perhaps a clearer example of what I'm talking about.
http://www.extremetech.com/gaming/131615-diablo-3-the-blizzard-sweatshop and
http://www.cinemablend.com/games/Beware-Diablo-3-RMAH-Gamer-Loses-149-Auction-House-Bug-44100.htmlOh, and I don't prefer the other game more, they are just examples of "having no underground trading or in game cash sales". For example Borderlands 1 and the Borderlands 2 game out shortly have ZERO chance of underground trading. It's Single player, multiplayer and PVP. If someone cheats, they win nothing. It's the same as cheating in a game of football by shouting "offside" every couple of seconds to give yourself a penalty. Totally pointless and if you try it no one plays with you anymore. Just try it in Borderlands, hack infinite gold or all the items, it makes no difference. The value is in playing the game, not having a +100 stat. The value is in swapping with friends, not selling a virtual item.