If tractors with closed software are such a problem, why doesn't a company build old-school tractors? Heck, you could use a 1980 design, currently selling second-hand for $40-60k, based on expired patents.
Farmers need same-day access to replacement parts, which means a dealer with a full stock of parts within driving range. Belarus/MTZ tractors are low tech designs but have about one dealer in every state.