It baffles me as to why. I think it’s hilarious how Linus is so careful to not break user space (for good reason) and all the user space libraries break every week.
Because every distro runs it’s compilers with a variety of flags and safety features and library versions and ABI quirks that make supporting stable ABIs a pain in the butt.
Distribution maintainers pretty much do whatever they want with the OS level ABI. That on top of whatever those user space libraries want to do anyways makes native application ABI stability basically impossible.
Again, how do Windows and macOS (to an extent) solve this? It’s possible, just not incentivized. Show me the incentives and I’ll show you the outcomes.
I think the main thing is that it's common for apps to bundle their dependencies. The default for Linux is to use the system libraries for everything - not just glibc but also things like zlib, libpng, etc. As a result you have to go to significant extra effort to make a portable binary app, e.g. linking against musl.
That's one of the attractions of Go, and to a lesser extent Rust; it's way less work than C to get a portable binary.
I think 90% of the problems I've encountered are due to glibc. They could easily fix all of them by adding a GCC flag that would allow you to compile against old glibc versions.
They'll never do that though because they are ideologically opposed to it.
