Lifecycle costs of machinery are pretty standard (especially after whatever warranty expires). And, of course, the farmer can avoid the risks of these costs by simply extending the warranty - then all the risk is on the warranty provider.

But the homework the farmer (or any purchaser - this same issue arises for medical imaging equipment, cars, busses, etc) should do is what will the service market looklike for his or her equipment after warranty. It's not easy to do this research - but the flip side is this: if the manufacturers have to sell unlocked service, they will charge more for the original sale. Economically speaking that may be better because the costs will be clearer.

My understanding is that it is not only cost that is problematic, but rather time. If you need to harvest, then you need to harvest now, not in 2 weeks. Whereas the dealer repair shops are not always available in those time frames. Especially not if you are in the field and have to unclog something, and then need a dealer-only code to re-enable the in-failure-mode part.

Your understanding is correct. It doesn't matter if the equipment is free: if it breaks down during a planting window or harvest season you stand to lose significant amounts of money.

Dealers may not have the parts, may not be able to provide the repair without calling in a technician, or may be located far away.

People are talking about R2R making things more expensive but the opposite can be true: service centers can often be lossy operations, so if you have to service machines at a lower rate (because people are DIYing it basically) it stands to reason you no longer have to price that in. Scaling out repair literature and part availability is cheaper than the actual service.