Trust me, a fully mechanical film camera does not take a rocket scientist to make it. And yes, I do know what I'm taking about. I was a machinist for many years before getting into racing cars, and have the trophies and awards of excellence on the wall. A good machinist/race engineer can make just about anything. You can make an entire car using reverse engineering, it happens all the time w/ high tech race cars, especially in F1, and all you really need are the photos. Race cars are many, many times more complicated, and built to much better tolerances than a film camera. They have to be, people's lives are on the line.
There is absolutely no reason someone couldn't take one of the simpler mechanical cameras apart, use an old fashioned micrometer and other basic machine shop tools, and make a similar camera. The stamped parts (which are a cheap way to mass produce anything) can be made w/ even better tolerances if it's a one off prototype. Today, many of the parts could either be 3-D printed or injection molded w/ today's plastics. Optics could be easily measured, and the results fed into a CAD machine and ground automatically.
Come on people, you can make a camera out of a shoe box or a beer can! But all this is besides the point, and way over the head of someone who has never done any of it. The idea here, as I see it, is that a modern camera manufacturer is saying they will build and introduce several models of new 35mm SLR film cameras. That I will believe when I see it, but that's just my opinion. The rest of what I wrote is based on actual experiential knowledge, and a ton of people out there are much more more capable and experienced than I am.