They were recorded on tape with microphones. The sound engineer then did the mixing on 2 way speakers is what you mean. Yes, I also know that most highly rated sound engineers were over 50 and had lost most of their hearing (I also favor tone controls on my gear, so I can correct, usually bright, recordings). Also, a lot of those speakers you mentioned were first made when highs only went to 16khz and not 20khz like today (same frequency response of a stereo lp).
Anyways, it's what I hear with 2 ways, a dip in frequency response around the crossover point, which is a higher frequency on a two way than it is on a three way (500hz to 700hz on a three way and 1000hz to 1500hz, ouch, on a two way).