The same way having a smithy in battle parties to pour potions on metal based monsters to weaken them works. It doesn't. I think havin them as a bazaar works but I can't imagine how they were ever meant to completely take the place of a full AH.
I can't either, but they WERE supposed to do that. It's just an interesting mental challenge really.. what was he envisioning there?
Also you brought up another good point. The crafting and gathering classes were intended to be used in group play right along with the combat classes. How was that really supposed to work?
I could only come up with one possibility for that one, and it'd only apply to large-scale endgame activities. Here's the scenario I'm thinking of here.. You've got a large group of people (40 or 50-something people). About 80% of them are combat-oriented in some way, melee, caster, healer, or tank. The rest of the group is made up of some sort of logistical support corps. Crafters sitting in the back, repairing or altering weapons and armor throughout the fight as needed, with gatherers collecting materials for them to do that. It would even be possible to set up an encounter to facilitate this with materials around the room for the gatherers to go get and bring back to the crafters to support the overall effort.
It would be a really interesting logistical puzzle, and add a depth to raid encounters not previously seen if it could be pulled off.
Of course what happened is that it was complete nonsense; which is what is going to happen to a system like that 99 times out of 100.