Again, there's more than the OS kernel that a programming language will need to interact with. You don't go through syscalls to make an X11 window or read keybo

Again, there's more than the OS kernel that a programming language will need to interact with. You don't go through syscalls to make an X11 window or read keyboard/mouse inputs or draw graphics. There are thousands of utilities that are meant to be usable cross-language, but in actuality use the C ABI (well, at least one of the 176 C ABIs there are).