In the '50s people used to hook up an amplifier driven by an oscillator to the capstan of an analog tape machine, adjust the frequency for the tape speed they wanted, make a copy at the desired pitch and then splice the "pitched" copy back into the master tape. In the '60s you copied the track onto a mono machine, cued it up and then punched it into the vocal track. There was also the German ELTRO rotating head device which worked very much like a digital pitch shifter. We had one for a while at Motown.
The "revolution" was the Eventide Harmonizer in the mid '70s. This was what Auto-Tune replaced which put a Pro Tools system in every major studio control room in the world.
