Heavy regulations are the reason why we have the John Deere semi monopoly. The regulatory entry cost is in the millions for any new player to enter the market so no one wants to compete and provide better service.

This is just not true - their machines are purposely opaque and loaded with DRM. Regulation in this area could potentially make the entire system more efficient and cheaper for everyone at the cost of JD's predatory practices. In addition to owners there are lots of independents who could work on JD equipment, but they are all literally locked out.

the cost of starting a company that makes a line of tractors combines and sprayers is probably second only to an aircraft manufacturer in difficulty and complexity

So are for some regulations but not others. I think that is most people's stance. It's more constructive if we talk about which specific ones.

I call bullshit until you cite evidence. Farm equipment doesn't even need to comply with road vehicle requirements. What special regulations does a farm equipment manufacturer need to comply with that don't apply to any other industrial manufacturer?