Actually, to the contrary, some of them ARE being made nowadays. However, the prices of the newly produced milsurp reflect the real cost of their production at present times. The prices of some original milsurp are still LOWER!
Examples:
-MOSIN–NAGANT MODEL M38, NEW MANUFACTURE 2021 YEARS $1,099.00
h ttps://westrifle.com/index.php?main_page=product_info&cPath=23&products_id=2392
-New production-bolt action rifle SAR K98k Sportmatch in caliber 8x33, similar to Mauser K98k € 2,980.00 h ttp://www.sar-shop.de/epages/61028398.sf/de_DE/?ObjectPath=%2FShops%2F61028398%2FProducts%2F98.637
-HMG® Sturmgewehr STG-N $1,799.99 h ttps://www.hmgunworks.com/product/hmg-sturmgewehr-stg-n/
That Mosin is not exactly a new firearm. Old parts are being used, some restamped, reblued and put together (without all that much care it seems) with the new barrels. Interesting project, but one can still find better looking, actual Mosin rifles around.