Oh really, if profit blows on it that much, then people wouldn't make it. No one makes it to 100 just to make his or her own food.
Per unit, it really does blow. What makes Cooking different is that everything
is consumable, and thus the market has a very high turnover. Cooking for gil is based around mass-production.
To make a significant profit requires you to procure your materials in the most cost-efficient manner possible (spending a few thousand extra buying a stack of materials off the AH instead of an NPC can wipe out your profit), and move bulk amounts of product quickly.
Knowing what I do now, I never would have leveled cooking on my main character. A mule (with some expansions to MogSafe and Inventory) would have worked much better.