Part of the reason Open Source eclipsed Free Software was that it actually delivered on the promise. Open Source aimed squarely at corporate buyers. They didn't hear open[ly available] source [code], they heard open [to competitive tender second] source. And that's a great economic argument for a company that uses a load of software. Companies love having second sources, because two competing vendors are less likely to lock you in and price gouge. An open field of an unbounded number of second sources makes accountants very happy.

Free Software, in contrast, promised user empowerment. It came with a set of freedoms and the guaranteed rights to make the software do what you wanted. You, the end user, weren't to be constrained by the set of things that a vendor decided your computer should do. It could do whatever you wanted, you could build on the work of others to do it, and you could subsequently share your work to further empower other people.

And almost no F/OSS delivers on that promise. I have a PhD in computer science. I'm on the C++ standards committee. I have written code in OS kernels, compilers, and some of the lowest-level bits of modern systems. I've also written bits of a GUI toolkit, text layout engines, and other bits up and down the stack, even the occasional bit of JavaScript for the web. And yet, to me, most F/OSS applications are simply black boxes. If they don't do what I want, I have no more chance of modifying them than I do MS Office or macOS (actually less, because both of those have rich scripting environments). The only benefit I have is that it didn't cost anything, but my time is valuable and I'd happily pay a little bit for something that was a closer approximation of what I want from a computer.

Imagine how it looks to someone who doesn't program for fun.

And what does the FSF do to address this? It gives the world a more complex software license. Because surely that will be the thing that finally makes all software empower users! The fact that now exercising the four freedoms with their software comes with more legal risks will obviously make more people realise the benefits of them!

People who are serious about Free Software should look back to Smalltalk and Lisp systems, where every part of the system was introspectable and mutable. They should look at the amazing research in the last couple of decades on approachable end-user programming languages. They should abandon siloed app abstractions that exist to keep people locked into single-vendor ecosystems and build small, modular, reusable, components. Computers could be so much better than they are, and Free Software could enable system designs that are impossible with a COTS proprietary model.

EDIT: To be completely clear: I am 100% on the Free Software side of this. I want computers to empower users and I want to remove obstacles to this. I just think that almost everything the FSF has done since the publication of the first version of the GPL has been a hinderance to that agenda.