This does happen in Linux till some extent. Look at wayland for example. Broken on nvidia hardware because nvidia favors its own implementation.

The reason why this does not happen with Linux kernel is because Redhat and Canonical go to great lengths to backport kernel patches, which by proxy affect all the distos based on them. Also because Linux desktop is not big enough for OEM's of the majority of PC users to care about.

Android is a flavour of linux that went big. The fact that OEM's can clone the kernel and put their own drivers into it without being forced to update is what causes the most grief in Android world.

Linux proper, ie the kernel, allows things like modules and has a powerful userspace. Most purposes are met by taking vanilla Linux and dropping some modules and userspace applications on it. You don't have to do a hard fork of the code.

But if you're talking about distros (or some vauge distro-like prepackaged blob of Linux + userspace), it does happen. There are a lot of specialized Linux distros out there, and they aren't all on long-term support with security backporting.

It happens with Windows. It has nothing to do with openness, it happens with all OEMs.

It is. The kernel is GPL; the copyleft license protects the commons from exploitation without releasing the source code, which allows people to fix these things. It does happen to Linux userspace though because a lot of that is not copyleft (which is fine, people should decide each component themselves).