But AFAICT the glibc dogma is based on the premise that it would be impossible for a large, complex project to have backward compatibility without making regula

But AFAICT the glibc dogma is based on the premise that it would be impossible for a large, complex project to have backward compatibility without making regular changes to the extant interfaces that it provides. Yeah well tell that to the engineers of HP-UX, IRIX, and Solaris, because all of those managed to produce libc's which were backward compatible. Sun Microsystems even legally warranted Solaris and therefore libc, they were that paranoid about backwards-compatibility. That's not the issue. The issue is that glibc is developed by people who are not and never were system engineers and instead of learning from the masters, asking them how to do it correctly, or sticking with BSD when its situation was dire, they just decided to re-invent the wheel. One does not simply re-invent glibc from first principles, especially so if one does not have the requisite insights and experience, which they didn't and they still don't, and most likely if they haven't by now, never will. GNU developers are a lost cause. Just look at how long it took them to "discover" versioned interfaces with linker map files, something Solaris system engineers have been using since the early '90's of the past century, and everything becomes crystal clear, if one knows the Red flags. That's one Red flag right there, "late in phase and unlikely to ever catch up".