I don't know about > 100 years ago, but I strongly suspect that the reason snoring is more common now than it was in the early- and mid-20th-century is because it's so much less common now to have one's tonsils taken out. In my grandparents' and parents' generations, it was typically a standard practice, at least in the places where they lived.
I'm well within the "healthy weight" band, but I had sleep apnea until I was 25. I was finally able to find a doctor who was willing to take out my tonsils after years of problems with them, and got amazingly improved sleep as a side-effect.
I had my tonsils out a decade ago and I still snore and wake myself up all the time. For me, it seems that weight has more to do with snoring than my tonsils did. When I'm thinner, I don't snore. When I let myself go, I do.
It's not by choice. I partially crippled myself in an accident and am still recovering. I had to learn to walk again and I still cannot lift anything with my left arm.
I'm well within the "healthy weight" band, but I had sleep apnea until I was 25. I was finally able to find a doctor who was willing to take out my tonsils after years of problems with them, and got amazingly improved sleep as a side-effect.