Some mount items are bound to the original player - so you must develop the related profession in order to learn them - while others can be sold and traded. Some mounts require you to be skilled in the related profession in order to use them (especially Tailoring and Leatherworking, plus a couple of Engineering mounts), while others can be used by any character on your account. We usually indicate above the mount whether it can be traded or is bound, and whether it requires a specific profession to be able to use.
The thing I liked best about the wide shuffle of those days was that it made ALL of my alts feel valuable. I'd get some ore some was sent to the miner to be smelted and then on to the blacksmith for belt buckles. The rest went to the jewelcrafter to prospect. Some of those got cut, the rest got turned into jewelry that was either sold or disenchanted. The enchanter then converted those mats into scrolls. Meanwhile the army of alchemists transmuted that expansion's elemental material (volatiles, sorcerous, etc). It felt like a whole business operation.
I think that's server dependant. I make a lot of Golems, but the price on my server is high enough that you could buy all the living steel and still make about 20K (almost 200kg on AH). Its just that you proc all the way up the chain. You proc 20% of your trillium, and then 20% of your living steel. SoH and Ghost Iron are such low effort farms, too. 20% of 180 Trillium Bars at 500g is 18k more profit, 20% of 150 Living Steel at 3500g is another 105kg. That's an extra 25k profit per Golem. If they stop selling stockpile them for the next expansion, they always boom with the price of herbs. And a consistent 20% proc rate is the opposite of RNG, its extra free stuff as a benefit to completing an extra quest (not to mention for new alchemists the investment of leveling Vanilla Alchemy). You're looking for some get rich quick scheme, where the real way to build wealth is patience and volume. No market is going to be viable because you want it to be. Only because you make it viable.