As the author notes, developers, doctors, lawyers, etc. know their value and charge accordingly. A developer who charges $0 for his work product must, therefore, be making up that value elsewhere. Most major Open Source projects certainly are.
Chrome, Linux, MySQL, and lots of other big names all have corporate backing. Large companies paying people to build software to advance their agenda. Commoditize the Operating System to sell more servers. Control the Browser to keep the rug un-pulled from your web empire. There's really not a lot of pure charity to be found.
True, you do find the occasional artiste working away for no money, living the officially sanctioned stereotype for what an open source developer is supposed to look like. But I tend to hope that he knows the score and is therefore looking out for his own interests.
There are lots of good reasons to develop open source. But I don't consider "charity to big companies" to be one of them.