They're about the last gasp of the surplus rifle market. While you can still find a few Czech and Yugo Mausers for not too much if you know what rock to turn over, the Krags, and Springfields, 1903s/'03A3s, P.14s, Enfields, K98s, Carcanos, Arisaka, and even K-31 are all somewhere between scarce and gone. Even Garands and M1 Carbines have been coming through the CMP in fits and starts -- like an engine running on the last fumes in the tank.
Weapons technology has moved on, the armories aren't making any more of these, and eventually they will all be bought up.
And that trend happens to collide with the huge growth of gunnuttyness that has overtaken large segments of the population in the last 10-15 years. There's more of "us" now than ever, and we all want a piece of that legendary good old surplus stash -- before they're all gone!
Supply and demand. Folks used to say, "you'd better grab one of those Enfields while they're cheap. They're ugly, but someday you'll wish you could still find a cheap Enfield." Now, all that's left is Mosin-Nagants. Still cheap, because the Soviets and their satellite states made more of them than they did loaves of bread for their people. Still about as good as ever -- which isn't terrific compared to the competition, but sure is better than most people THINK. But now we all have the lesson of eventual scarcity to nag us into buying one (or a dozen) before they're all finally gone.