That's all true, but it's only true if you're making thousands of them a year, not hundreds. Much of what was stamped could be machined instead, you use stamping for economy and labor savings.

WE Hawthorne Works in Chicago was similarly large, and to build in quantity you'd need it to be just as large now, but to build a couple hundred strowger switches a month? Not as large.

The hardest part of bootstrapping to 1930 is making copper wire - doubly so for wire suitable for electrical coils.