This assumes that LLD has been around much longer than it has. Apple first sponsored development of LLVM, before clang or LLD existed. Then they sponsored clan

This assumes that LLD has been around much longer than it has. Apple first sponsored development of LLVM, before clang or LLD existed. Then they sponsored clang development. LLD came much later. I believe Rui created LLD at Google with an intention of linking Chrome on Windows. That was a very different use case than what Apple had in mind. Eventually LLD abstracted the target object file, could link ELF executables, and had a good design for furthering support for mach-o. Facebook is developing that in LLD surely to support linking their iOS app much faster. Apple remains disinterested from what I can tell.