Production for that kind of gun is difficult on a small scale and very expensive to set up on a large scale, so they'd need to sell LOTS of them to turn a profit.
7.92x33 ammo is nonexistent, pretty much, so someone would have to set up an ammo production line just to make ammo for these guns that a manufacturer hopes to sell. (Well, and to sell to the few NFA collectors who own originals.)
The gun would have to be redesigned to escape US NFA classifications, so it wouldn't just be a matter of working off the old blueprints.
And, then there's the sales question: What's it for? Who's really going to buy one? A handful of military collectors? A very small number of general interest shooters? None of the modern tactical types are going to be interested in that as the tech is old enough to have lots of drawbacks compared to a modern-ified AR (or even AK). (And won't have the billions of mags, and thousands of bolt-on do-dads to make it more go-fast-friendly, and all the product and inertia that support the AR and AK in American shooting culture.)
So you've got 100s of millions of $$$ to set up and build them (and mags for them and ammo JUST for them), with a legitimate potential to sell a few thousand rifles. Probably never more than 30,000 would ever be sold. (Admittedly, a guess.)
There's just no return in that investment.
