Well I was one of the people who traded goods between vendors, and let me tell you, it wasn't a long term profitable experience. They closed down the supply/demand trading due to a bug/glitch, not due to the normal supply/demand.
Yes, you could make good gold trading between towns, but this was offset in that you could only do it ONE time. This wasn't something you could do all day between vendors. Once you averaged the price down some, the vendor price adjusted automatically so after a quick time it wasnt profitable. So, if one vendor sold bolts for 10 gold and you found one that bought them for 20 gold, after about 10 trades the prices were averaging out so you weren't making much gold.
The only way you made good gold this way was if you found a vendor that was for some reason extremely low, or extrememly high (due to players in that area buying). This didn't happen alot, but every so often. Like I said, having did this type of trading on my craftsman for a long time, you hit "spurts" where you could find a vendor somewhere and make some gold from him. Otherwise, the vendor prices didn't change unless someone happened to really need something and bought alot.
This wasn't a cash cow. It was a quick gold burst. You played the game normally, and once in a while recalled around to all the vendors checking prices to see if anything had been adjusted. You didn't waste your time when prices were close, because you could hunt and make gold alot faster. Bolts at one guy 8 gold, bolts at another guy 13 gold.. mmm not worth doing that much. Now, find a guy buying bolts for 22, and a quick hundred k in the bank with some cross trading.
So who made gold faster, some blackrock ijiot who runs to a shadowlord, gets a cloak, and sells it for a mil? Or my craftsman who takes the time to mark books between vendors, recalling about, cross trading, and after a few hours has 500k. You tell me.
It was stupid to elimitate the old method due to a bug. What you do is fix the bug so we can continue with the supply/demand method which WORKED. It allowed us to hunt for leather and actually sell it. Or gather up arrows/feathers/wood and sell that to npc fletchers instead of saving up and having 50k in the bank. Guess what, scripters cut so much wood they sold it for 2 gold on their vendors. Guess who i can sell wood to that I cut.. NO ONE. Either use it, or maybe get ok gold from a npc. Can't do that anymore, so it piles up.