Insider Trader is a column about professions, written by Basil "Euripides" Berntsen, who also writes Gold Capped. If you're looking for general auction house advice, you'll find it in Gold Capped; Insider Trader focuses on specific profitable markets.
Got this from Thoorull on Steamwheedle Cartel (EU-H):
This is an excellent observation that's been bugging me for a while. Cataclysm is just around the corner, and everyone will be leveling new characters and doing trade skills from the ground up. It sure would be awesome to have the ability to turn readily available mithril and iron into much harder-to-find truesilver and gold. Let's look into what trade skill cooldowns really do.Blizzard has a long tradition of taking some "special" mats or crafts off of cooldown eventually, to help players along as content progresses. There are many cases: The Burning Crusade and Wrath of the Lich King cloth, Transmute: Titanium, Smelt: Titansteel, etc. What I completely fail to understand is why some now-trivial transmutes are still on a cooldown. Not just plain cooldown, but the all-important one which is used also for current epic gems. This includes vanilla iron, truesilver and essences, and TBC primals in addition to the said current-content epic gems and eternals. It completely baffles me why I can transmute a bajillion of titanium bars or current-content meta gems (as long as I have the mats) but not some old and obscure stuff.
Cooldowns are a limiting factor of supply. Economically, some items can't be available with virtually infinite supply, or else the items they can be made into would become cheap, and therefore less valuable, in the eye of the average player. Part of what Blizzard does (extremely well, in my opinion) is balance what players want with what they think they want.
You can't always get what you want ...
How much fun would it be to play WoW with cheat codes? Aside from the initial fun you'd have breaking all the old rules, how much time would you actually spend playing the game if you could make everything without working? Items would lose their value from your perspective, because you could simply make whatever suited your current wants the most. The value of an item is defined by its desirability to players, and scarcity is an important part of the equation our minds calculate when we're comparing two items.
You see where this is going? One of the most long-standing design principles in WoW is that while you may be able to get a couple of cool items with professions or gold, the truly valuable objects are the ones that can't easily be bought. There are ways around this with the GDKP system and raid teams that are willing to sell achievement runs; however, these are infrequent enough that Blizzard hasn't yet taken any steps to prevent them. Basically, though, the larger proportion of the game that is somehow supply-constrained, the more we seem to enjoy it and value the rewards we get for playing it.
All that said, cooldowns are only one way of limiting supply, and they only limit supply on commodities. Right now, you're not going to find many alchemists transmuting iron to gold, unless they're unable to transmute something like an epic gem. Still, there's nothing you can make from truesilver now that would break the endgame raiding balance, so why can't we transmute it all day long?
... but if you try sometimes you just might find you get what you need
The answer might simply be that the devs simply didn't think of it; however, I suspect the limits exist partly to protect low-level miners. Gold and truesilver are both in rather short supply and are a mainstay for low-level miners trying to make money while leveling. Still, there are a ton of new items we'll be interested in making while leveling trade skills through Cataclysm, now that epics will provide us the possibility of more than one skill-up. This demand will only add to the not inconsiderable demand already there for old world mats like gold and truesilver.
Honestly, low-level miners don't make a huge amount off really rare ores like this anyway, and if they were able to sell their other more common (and easier to mine) ores like iron and mithril to people looking to transmute them into these high-demand leveling mats, they'd probably end up better off than simply being able to sell goods from rare veins for more than they currently do.
Also, while Blizzard tends to choose the path of fewer changes on the live realms with its usually conservative patch notes, all bets are off for the next expansion. I'd be completely unsurprised if we found that the transmute cooldowns only slowed down production of the current endgame tradeskill items.
Insider Trader takes you behind the scenes of the bustling subculture of professional craftsmen, examining the profitable, the tragically lacking and the methods behind the madness.