GM had a few large auto plants in north NJ last time i was there.. I am not sure if they are still open?? Ford might also have had a good size plant in North NJ.. Right off Rt 9 I think..
I have a few Electronics magazines from the mid-1940's that I found in a used book store a few years ago.
Looking through the advertisements shows at that time perhaps 75% of the electronics industry was located within a 100 mile radius of New York City. California was clearly behind either NY or NJ in electronics manufacturing.
Jack