Win32 is quite extensive for an OS API. It covers the space from low-level stuff like syscalls and page allocation and all the way up to localization, simple media access and GUI. So everything from glibc, libsystemd, libpam to libalsa and egl on Linux side. And it is all stable.
Microsoft also provides quite good stability for DirectX and other extension APIs. You can still run old .Net apps without issues as long as they didn't pull a Hyrum's Law on you and depended on apparent behavior.
Sure, win32 contains GUI bits, but modern apps do not use those GUI bits.
OpenGL and Vulkan ABIs are also stable on Linux, provided by mesa. The post is pretty focused on the simplicity of win32 though, which is what I'm refuting as being as relevant today for new apps.
> As long as they didn't pull a Hyrum's Law on you
It is guaranteed that they "pull a Hyrum's Law", the question is just what apparent behavior they relied on.
> Sure, win32 contains GUI bits, but modern apps do not use those GUI bits.
Which is probably why so many "modern apps" look just like "modern" Web pages running on the desktop... i.e, why so many "modern apps" suck. They freaking should use those GUI bits.
Microsoft also provides quite good stability for DirectX and other extension APIs. You can still run old .Net apps without issues as long as they didn't pull a Hyrum's Law on you and depended on apparent behavior.