Casually following milsurp prices for the last 8-9 years, I noticed that...
1) US WW2 milsurp prices have been high relative to other milsurps for that entire period. Maybe there was a jump around Saving Private Ryan or Band of Brothers and the glut of WW2 first-person shooters that really kicked off in the early 2000's with Medal of Honor and the original Call of Duty
2) Prices have steadily risen for Lee-Enfields (and the non-Lee M1917/P14), especially Long Branch guns, so at some point, there's been an increase in Canadian milsurp fanciers
3) Some of that interest seems to have spilled over into other more modern milsurps like K31s and AG42s. Haven't paid attention to if this has affected prices for older milsurps or ones chambered for rounds that are harder to find
4) SVT-40 availability has dried up and it seems like Russian and Yugo SKS aren't as common as before. I suspect that many of these are ending up in the hands of militia in the conflicts in the ME and Ukraine
Milsurps are just a weird market in general because the guns are sold far below both historical and modern manufacturing cost (as guns like the Springfield M1A or AIA Enfields show). Many were made under command or wartime-economy conditions and with eye-watering economies of scale, and all availability comes from countries liquidating old war stocks - for example when India sold off their captured Pakistani No.4 Mk.2 rifles or when Ukraine or Russia periodically cleaned out stores of SVTs and Mosins and China cleared out old holdings of SKS rifles. Most times that occurs, we get a glut of rifles and their prices drop like a stone. Furthermore, in many of these cases, there's no way of knowing what further availability will be like. In the future, guns could end up being supplied to war zones instead. Bureaucracy or politics may keep them in the warehouses or sold to other parties as a political or diplomatic favour. Actual inventory may be regarded as state secrets. We may be able to confirm if (for example), all Swedish AG42Bs have been sold, but good luck counting how many SMLEs India has stored or how many forgotten ex-Soviet warehouses of SKS carbines remain and if/when they'll be available as surplus.