It's actually a discount in that regard since most people would have to spend considerable time learning how to take that photo.
It's a perfectly good starting place for a price. And nowhere did he say that price wasn't negotiable.
It's similar to buying anything on the market - A toaster would cost hundreds of thousands of dollars to build from scratch (http://www.thetoasterproject.org/), but no one pays that much (not does any manufacturer expect that much) since no one is really going to build one from scratch.
The author's argument gets really weird at the end when he claims that if someone misappropriates the image, he would charge the cost of his camera, his laptop, his software - the whole shebang that went into it. It's a very strange way of computing the loss of value to him. The loss of value could be zero (if there was no buyer for that image in the first place - a lot of photographers take excellent images without anyone actually buying or wanting to buy them ever), or it could be many thousands of dollars if it is a piece of art that is highly valued. Basing the value on the cost of the equipment that went into producing it does not do justice to the image either way.
I also suspect that he would be happy to license uses of that photo for substantially less (though I'm VERY curious as to what that cost is, actually) to magazines and other people wanting to use the work on a single-use basis.