Because most of them depend on UNIX being there in first place, aka all of POSIX, alongside Khronos APIs. Additionally, most C libraries tend to come via UNIX

Because most of them depend on UNIX being there in first place, aka all of POSIX, alongside Khronos APIs. Additionally, most C libraries tend to come via UNIX package managers directly, and then consumed via CMake, pkg-config or what not. I do agree Rust dependency trees are a problem, for security, and always compiling everything from source.