Reproducibility of mechanical objects is only the case in the modern day! It used to be that reproducing mechanical parts was difficult enough that a particularly sophisticated part could be just as locked-down as a particularly sophisticated bit of software is today.
For an illustrative example, imagine that a part on your tractor suddenly becomes a bit of twisted, wrecked metal.
These days? You ask someone else with the same tractor to send you some pictures, pull their part out and measure all the holes and their positions and tell you what the bearing surfaces are made of, you scrape off some slivers of your wreck and assay them to figure out what alloy it's made out of and how it was heat-treated, you go and machine a test piece or two on your mill and try it, you buy a bit of bronze bushing off mcmaster and it works, etc. Maybe someone else has already done this and published a CAD model and instructions! We have solutions for this.
Back then? You have no designs. You have no way to communicate with other people who have a complete working part. You might be lucky enough to remember what bits the part connected to if you'd looked at it before. You may have some idea what the intended geometry was, but you're never going to figure out that the geometry is actually just a few degrees off right angles because that keeps you out of a complicated kinematic singularity that blows up the part every time you turn left. You can guess at some of the materials, but systematic classifications of iron-carbon alloys don't exist so all you can say is "it's some kind of steel". Even if you figure a lot of this out, there's no real way to write it down or share it with people because a lot of the terminology for representing this stuff simply doesn't exist. Even if you make a functional part, its expected lifetime is months rather than decades.
The original creator, by comparison, can just buy a new block of their supplier's "Alloy Number 5", throw the forging dies back on the presses and stamp out a blank, slap the blank into the jig that presents every hole to the drill press at exactly the right angle, put the part through their proprietary heat-treat process, and then ship you the result. Those dies and jigs and heat-treat protocols are exactly the same kind of proprietary protection that a git repo full of source code is today.
If you look at hydraulic and pneumatic fittings, you can see elements of this lock-in still extant in the modern world. Everyone had their own thread sizes and thread geometries for their own tools, getting them to interoperate was impossible unless you had the right adapters, and you could not make the right adapters unless you were a dedicated specialist in hydraulic fittings. You were locked in to your tools provider's pneumatic toolchain in exactly the same way that people are currently locked in to their current power tool brand because they own $50k in tools and battery packs that agree that they're made out of a specific manufacturer's 18650s with specific voltage drop and internal resistance and etc etc etc. (go watch the torque test channel's segment on battery adapters a bit, it's enlightening! - https://www.youtube.com/watch?v=WgJI8Ikrd6Y).
(if you watch enough of Forgotten Weapons, you'll also hear things like "X bought the design for Y gun but it took them 3 years to transfer the tooling and get it up and running" - that's the stamps and jigs and heat-treats and everything that I was talking about earlier, and if those tools were destroyed a gun generally became totally unmanufacturable and had to be redesigned from scratch to continue production, and those redesigns frequently failed to perfectly reproduce the original!)