Linux distros are not by any means walled gardens. You can always install new software by building it from source or often from just downloading something someo

Linux distros are not by any means walled gardens. You can always install new software by building it from source or often from just downloading something someone else built (as long as it's statically linked or you have the shared libs). Windows is also not a walled garden but to a lesser degree than Linux. It is far harder to get a "standard" build environment up for windows simply because Microsoft refuses to distribute the UCRT (or VSRedist) build libraries in a form that doesn't require manually digging through installer internals or setting up Visual Studio. It can be done for free & legally but it's a significant pain in the ass. Regardless of how annoying it is, there is no financial/legal barrier to building software for windows and you can trivially install 3rd party software or even execute it without installing. Android I somewhat agree is a walled garden in practice (certain features are limited to gApp/play store apps only and setting up 3rd party play stores or apps is annoying) but by the simple fact that you can build apps for android or install them without any financial or legal barriers, it can't realistically be called a walled garden (maybe a hedge maze might be more accurate). MacOS isn't entirely a walled garden despite getting pretty close (kinda like a worse dev/install experience from windows + *nix). iOS however is 100% a walled garden. Point being that out of every OS you mentioned, exactly 1 of them qualifies and the rest do not (despite having anti-user/anti-competitive practices)