30 years ago the Enfields, Mausers etc were also 100$ guns. Mosins have appreciated 100% in ten years? Thats not bad. Even the SKS is appreciating quickly as we speak. For example Wholesale sports boxing day sale last year was 159.99, this year it is 205. That is huge appreciation in one year and there are rigid supply forces behind it. We will never, ever see a 159.99 sks again.
I got my first Chinese SKS new in the grease from a dealer for $129.99 2 years ago. I think they're about $350 used nowadays.