>>2713272This.
It's not like there's a ton of complex, precise moving parts to figure out. Just buy a couple of Holgas, make some injection molds of the parts, and start selling them again.
Honestly, part of the thing with Holgas to begin with was the fact that their parts were shit. I'm not saying that as an insult---hell, I own a Holga---it's just part of their whole schtick. They aren't light tight. Their aperture dial doesn't actually do anything. Their lenses are inconsistent at best. Honestly, it'd be relatively easy to make one.