Windows is slowly getting more walled. For example, it’s not possible anymore to freely define file type associations in the registry. Windows only enables the user to do so via a very limited UI, which for example doesn’t allow custom icons, command lines, or custom groupings or forwarding of associations. Someone reverse-engineered the protection to defeat it [1], but it’s still a pain. Another example is that it’s almost impossible to change the UI look in ways not intended by Microsoft (which are much more limited now than 20 years ago).

[1] https://kolbi.cz/blog/2017/10/25/setuserfta-userchoice-hash-...

You don't have to pay anyone to sign a driver you write to use it yourself. With Windows you can write some software, but not all software. You have to pay Microsoft to sign drivers. The code that enforces that is the wall. No such code exists in a Linux. All is possible.

Wine is just a few clicks away in most distros or go to https://www.winehq.org/ and follow the instructions there. It can run quite a bit of Windows software. I've just spent a pleasant few minutes playing 3D Pinball for Windows - Space Cadet,

You have a point. Anyone can develop software for windows. It's not walled off at all. There are security prompts in place when you start doing unsafe things but you can pretty much do anything.

The only thing walled off is the source code but nobody is referring to that.

I think people are associating walled garden with closed source. This is not a consistent association because there is one operating system that is, in actuality, a true walled garden where the term fits:

iOS is a walled garden.

The characterization of the term here is entirely different from windows or Linux.

Thus the parent is also correct about his point. If you use a Linux distro exclusively with a package manager. It is effectively as if you are in a walled garden. It is just like using the app store on macos exclusively.

Linux can run floss and Windows software too.