More of Schultz's work looks at this [1]. Basically, a reward of 50% of the time is far more addictive for Julio and his pals than 100% (eg. the Staff of Beatings only drops 50% from The Butcher). Diablo 2 uses a traditional variable reward schedule for its loot system, as seen in most other RPGs. Diablo 3 uses gold (stick with me). You need gold to get the items the game requires you to have from the AH, and you're mostly burning the loot you find in-game for gold on the AH or other mats. This means that you're working on a small, 100% drip feed, which you eventually cash out in a predictable fashion. Not as addictive!
I don't agree with your assertion of a frustration loop being different. Diablo 2 could be just as frustrating if loot you needed didn't drop in time. One thing I think Blizzard has done very poorly is that AH transactions do not provide instant gratification, but take up to 48 hours to process(!). This means if you are in a rut, you'll have two days stuck in it, and perhaps just break the habit and leave altogether.