I think the article is based on a misconception. Just because software (including source code) can be obtained by anyone at no cost does not mean the developer

I think the article is based on a misconception. Just because software (including source code) can be obtained by anyone at no cost does not mean the developer was not paid to create it. The important question here is "why was this software written in the first place?" If you think that the purpose of software is to make money through licensing fees, open source doesn't make any sense at all. However, if you take a contrary view that the primary purpose of software is to solve problems (with revenue generation as an optional secondary goal), then it does make sense that a developer could get paid quite well to create something they give away for free.