Why weren’t wire ties used? Or twisty ties (the kind used in garbage bags)?
a) "Zip ties" were not invented yet (nylon was invented in 1935)
b) Twisty ties are thin metal wires covered by paper (plastic covered ones were not practical until the late 1900s). The twisty wires were a threat to cut into the wire bundle. They also rust.
Even in modern days with zip ties, lacing has a significant advantage in that zip ties have sharp "tails" that stick out from the bundle and cut your hands and arms when you reach into a compartment. Lacing lies flat against the bundle and has no sharp ends.
The guy that ran a computer shop I used to frequent was an ex-Bell tech, and taught me about using flush-cut snips exactly to avoid this. They've been a part of my toolbox ever since. They're also my go-to cutting tool when working on small electronics.
However, since it uses standard zip-ties, there's still the extra bump of the head on the finished tie, which can snag if you're pulling on the bundle.
Laces ensure the bundle is held together at fixed intervals for a long time, even in the face of vibrations, temperature changes etc.
https://www.hellermanntyton.com/competences/cable-wraps?comp...
Or, in bigger swithchboards, ducts like these:
https://www.hellermanntyton.com/competences/wiring-ducts-hel...