Although it's a good read and brings up valid points, the article has one major issue (an issue found in all of economics). It assumes everybody plays for money or to make a profit. Some people find crafting fun, fascinating, like myself. I cannot give a rats behind how much profit I make, but learning the process and mastering it is what makes it fun.
We don't even need to bring up subjective things like fun either. A major incentive for crafting lies in the experience levels you gain with it. That is certainly worth investing money in, so you can get to the higher money-making levels sooner; the market value of that service is folded into the disparity of crafting mats versus the items they produce.