You do have to work at it, same as if you were doing PVP or high-end raiding. It's not something you can just expect to do without preparation and experience.
OTOH, I made 20k this week off of Darkmoon cards, without addons, without dedicated farming or buying mats. Of course, I did prepare for this by having my level 85 scribe doing her daily Scroll of Wisdom for the last month and not really doing anything with the herbs I got while doing dailies on my rogue.