Mass production may be infeasible, but theoretically, I see potential here for print-on-demand production of rare and unavailable parts for vintage vehicles that are no longer in production.
That’s already a market with the Scan-print gig.
Takes some effort to scan complex parts but eventually you can get there.
Harrell essentially did just that. Guarantee you he does not have the geometry for those gears except as a scanned surface.
Manufacturers of commercial aircraft went down this road 2 decades ago, prototyping mockup components; and, working out issues before tooling up for actual parts. Now actual parts are fabricated to shed +10% weight over results obtainable with traditional machining/ fabrication techniques.
NASA needed a fuel injection assembly for an F-1 returned from museum storage. Traditional supply operations forecast delivery of +1 year. Printing a working unit was achieved in a abbreviated time frame.