But Bernina only appeared in the 50-60 in North America, right? So it was a newer brand than Singer (or even Pfaff) for people here. They didn't know about the durability. So the consideration that it was the "Cadillac" must have come from somewhere. Maybe they were already distinguable of their concurrents by their smoothness of operation... Maybe people where feelling, while trying it, that it was a high quality sewing machine.
I owned several vintage sewing machine, and most of them are coming from an unknown succession of owners. But the three Bernina I have all come directly from the hands of the original owner. It tells something... People don't part easily with these.