I agree that automotive and farm equipment have generally mediocre security track records and that, with the addition of remote connectivity, these issues are concerning. But all hyperbole and breathless reporting like this gains us is an excuse for repair hostility under the guise of "security."
That's what every other company has been trying to do too, not just farm equipment manufacturers. If you look between the lines you'll find that the "security industry" is largely in favour of corporate-authoritarianism. Thankfully, not everyone is stupid, and I suspect farmers are actually more likely to spot the BS.
If you're looking for some unreasonably secure device, obviously you have to bake an apple pie from scratch in order to ensure no steps in your supply line are tampered with. Current system has plenty of problems with which that's being used as a defense though, and the fact that those systems are so closed is what allows zerodium to exist in the first place.