Could it be that technology changed things? When the original "classic" Exaktas were around, they were slow klutzes to operate - and left-handed at that. It wasn't until automatic diaphrams and instant-return mirrors were developed (supposedly both by Pentax), that SLRs took off.
I'm old enough to remember articles in Pop Photo about "SLR vs. RF" cameras. Somewhat akin to today's "film vs. digital".
When I was in high school, I had a Montgomery Ward photo catalog, and Wards wasn't known for 'discount' prices. I distinctly remember that, around 1954, a Contax III cost $444 in that catalog. In those days, that was probably a good deal more than most peoples' MONTHLY income.
My original Minolta SLR, an SRT-101, cost me about $175 with a 50mm lens in about 1970. Last summer I bought a Maxxum 7D (from B&H) that cost $1,100. So that common influence known as inflation has played a part, and there is no, or little, hope that that will go away.
Read 'em and weep - I have a Leica M4-2 bought new in 1983 that cost me $800 for the body and about $450 for the 50mm lens. Still have them, and they take great pictures. I don't need that latest gimmick to photograph with. I don't need an M-8 (if and when it arrives), and I don't need an M-7, either.