Companies like John-Deere should be able to survive without abusing their downstream customers. Many farmers are importing tractors from China because they're cheap and not hostile to repair like JD is. Some people might call it a "smart business model" to sell interdependent services, but in the long-term it's suicide.

Whether or not you solve this through regulation, that's up to you.

It would be nice if companies could commit suicide faster, instead of dragging it out over several decades.