The reason why legendaries are so expensive in the first place is because Blizzard added vendor materials to them which cost a FUCK ton of gold to buy.
Goodluck starting out a new on your legendary pieces in your profession, you're going to sell it at a loss thanks to this garbage system.

Whoever designed these profession systems ought to be fired, but given Blizzard, they're probably getting a promotion.

It's so fucking lame that these vendor materials aren't taken out of the game. It would make the game a lot easier, both for crafters and gatherers alike.

Stupid garbage system.