The Argus C3, a 35mm rangefinder goes back to about 1939. I bought mine at the very end of 1957 or so and I remember prior to that drooling over the Exactas and such that were way beyond what I could afford. Plus TLRs go farther back, at least to the thirties. It might be that the post-WWII recovery of manufacturing in Europe and Japan combined with the relative prosperity of the 1950s may have expanded the market and encouraged more use by "the masses."