The John Deere tractors that get the right to repair people riled up are the big expensive computer controlled ones. It's an extremely niche market but definitely an important one as farming is extremely important to the global economy.
For the consumer level tractors which are manufactured in a volume which is more similar to automobiles, there appears to be plenty of parts in the market to fix them. Even the consumer level tractor parts with John Deere labels on them seem to just be rebranded cheap commodity parts much of the time.
