I agree with this to some extent.. but I think a text editor is a little different than gitlab. Even within the realm of text editors or IDEs, there are still successful paid options (not to mention that the author is conflating ‘open source’ with ‘free’).

With something like gitlab, people may pay for some ‘enterprise’ features, but they are also paying for support. Open Core and totally open source projects can be monetized by offering support.

Other projects are successful just by limiting who can use the open source software for free via different licenses.