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.

Economically worthless is a very bad phrasing, but the concept is very real (economists go with non-excludable, but that has an underwhelming impact on laypeople), software authors have a really hard time capturing the value they create.

I've always thought of it as the turn-style in front of the theme-park. Without that turn-style, the theme-part is economically worthless no matter how good it is.

Yes, that's the idea, but keep in mind that "economically worthless" has a literal meaning that is almost opposite of what you are trying to say.

And not only that... but a theme park without an entry fee is still a money-maker via snacks, drinks, souvenir cups, and extra-cost rides and line-skipping.

In much the same way that a company can produce an open-source product and charge for support, feature development, consulting, data feeds and sometimes SAAS operation.

I just mean you can't charge for it directly. "Utility" is perhaps what you mean. Note that the most important achievements (scientific and artistic) in human history were economically worthless for their authors, but have had enormous indirect positive economic benefits.

Yes but that’s not what the parent meant but in a money making way, and that has been something big companies realized a long time ago and capitalized on it. The general trend has been to create attractive gardens, get people used to them then raise up the walls. In the end even open source has stated to make a bit less sense to its creators and maintainers who are people and need to eat too

What is the market price of a copy of the Linux kernel, I ask?