I'm more curious about why there isn't a market to offer what farmers want. Why not make modern, serviceable equipment with open code and published APIs and schematics? This just screams "market failure" to me.
There's a bunch of stories about how pissed the users of farm equipment are with everything being controlled by computers that are totally locked down to the manufacturer. They're the kind of "easy agreement" story that flourishes. I don't doubt that they're true.
What I suspect is that this segment of the market is too small and too conservative to support a new manufacturer. The end result being not enough sales.
If you're buying a product that lasts 30+ years, and there's relatively little follow-on revenue after the initial purchase, then the market needs to be pretty big to support a manufacturer. And if you're new to the game, who's going to trust you for a 30+ year product life, when you've got no track record?
I'd love to see someone try though: you could try to promote the openness of the system as a counter to the "untrusted manufacturer", I suppose.
Meanwhile, "big Ag" is perfectly fine with an equipment-as-a-service model, since it gets capital costs off their balance sheets, and manufacturers are happy to play along, because they can get a much simpler and more consistent revenue model?
The biggest issue that bringing new equipment to market is incredibly expensive and you are competing with all of the green, red and blue (and now orange) guys that have been building equipment for generations. The new issue is looking for a revenue stream for the manufacturers. My Case while not on a service contract, has very few owner servicable parts to it. My '94 Kubota still does the job but Kubota makes about $200/ year on me at most since I can fix everything on it myself.
It is by no means a market failure, the market is working exactly as it's supposed to. It's just that people think that the market is there for the farmers when it's really there for the equipment and inputs manufacturers.
A big part of this I think is using electronic components and no chips / pcb, so you don't need to have specialized skills to repair and service.
E.g
The Lada, Combine, T42, and Mig 17 all being designed knowing they would have to use of the shelf "Soviet standard spring #2"