As for reinventing the wheel, it just might be that the Universal Mercury II is the simplest and most reliable high-quality 35mm film camera design that has ever been put into production.
Originally priced at $25 in 1939 to match the price of the Argus C3 (about $500 today), the camera was re-designed after WWII to accommodate standard film cassettes and marketed as the Mercury II between 1945 and 1952. The Mercury II emulates the body shape and size of contemporary Leicas but is otherwise entirely different, with a fixed, scale focus lens and a twin-disc rotary focal-plane shutter with exposures of 1/20 to 1/1000 sec. The 3" shutter diameter restricts the frame size to slightly larger than standard 35mm half-frame, or 65 images on a nominal 36 exposure roll.
The variable-sector shutter is derived from cine cameras and gives a consistently accurate exposure with each relatively slow and quiet rotation. Spring tension is relaxed and the parts count is low. The entire shutter assembly can be removed for service in a few minutes and the technical skills needed to clean, lubricate and adjust are elementary. I know this because I easily repaired my own Mercury when I first got it, using simple tools and basic instructions found on rangefinderforum.com.
Most of the 150,000 Mercury II's produced were fitted with a three-element coated f3.5 lens, with an optional f2.7 or even f2.0. Compared to conventional designs, the camera is quite odd-looking and slightly awkward to operate, but the picture quality is very good and the mechanicals give the impression that they are capable of a giving at least a hundred years of service with very little maintenance. The majority of the surviving Mercurys are now over 70 years old and if not still in nominal picture-taking condition, a few hours of cleaning, oiling and tinkering will likely get them going. The biggest cosmetic problem is that the aluminum alloy bodies have been prone to corrosion over the years, but even in the most extreme cases, photographic performance is unaffected.
If someone were to attempt to build such a camera today, they would be hard-pressed to duplicate the effectiveness and durability of this design. Flash forward to 2119. If 35mm photographic film is still being manufactured in the next century, there will still be fully functional Mercury II cameras to load it into.
Here's a good overview of the Mercury II:
https://www.mikeeckman.com/2014/12/universal-mercury-ii-1945-52/