Few companies experienced the explosive growth fb did, though many will claim to have done so. Hack made the existing codebase of php scale to insane levels while reaching escape velocity for the overall company to even attempt to transition away or shrink the php codebase, as i recall (i was an SRE, not a dev)
my memory is hazy, but when i started i was called an sre. Then someone made up the term "app ops". then it was production engineering. then I called myself an SRE when i was interviewing to leave fb.
Oh, and i was called a DBA before being acquired by google.
zeus likewise.