I think you mean a different definition of economic worth than the GP post. One meaning is the developer's ability to sell the software, the other meaning is the value derived by using the software.

I maintain an open source project that sits in a very small niche. Based on downloads, stars on GitHub, and comments on forums, I estimate that hundreds or thousands of people find it useful. I do get the occasional donation, but if I calculated dollars per hour that I have put into this project, it would probably be in the single digits.