This is false. I make a large portion of my in game gold through crafting. At the moment, only through the cooking and artificer professions. I suspect there is more gold to be made through the weaponsmithing and jeweler professions. I haven't tried them yet though.
It does take a bit more effort than flipping on the trading post. But only a bit.
You generally will not make a profit by crafting exotics here. The key to profiting with crafting is to focus on making crafting components - not end products. And also checking with the crafting sections on GW2Spidy.com to see if the current trading post prices will allow me to profit.
End products are generally worth less than the components that make them. Personally, I profit from making level 35-75 inscriptions, and cooking components such as Herbed Stock or Dilled Cream Sauce. A large part of the reason for this is down to people wanting to level their crafting professions in game. The crafting process in itself is worth more to a player than the end product it produces.
There are some things to bear in mind when trying this:
- Pay attention to crafting levelling guides. You can focus on making the components that these guides advise players to buy to level their crafting.
- Use spidy to check that you will profit off making a crafting component.
- Don't flood the market. Check out the current market to figure out how much of an item is available, versus how fast the product moves. Personally, I will list an item such as a rare inscription in batches of 10. Bowls of Dilled Cream Sauce have historically moved fast enough that I list in batches of 100.
- Never buy the materials needed to craft a component through the listed price on the trading post. Always use buy orders!
Granted, the specific items I mentioned above may well stop being profitable by the time anyone reads this. But there will always be other crafting components that are in demand, and there are other crafting markets that I haven't covered here.
Happy crafting!