As a tractor owner. Two things, the DPF & SCR (>=75hp) on a tractor is not a great idea --

1) Tractors are typically owned by low margin businesses (i.e. farmers) that need to be repaired in the field AND need to be repaired quickly, else you loose a crop. Adding complexity to tractors literally can cost the farm.

2) The actual emissions reduced is questionable. Tractors run significantly less than a truck, like 50-100x less often. Further there are at least 2x more trucks sold per year

3) To run the SCR system, the engine had to run hot for like 20 minutes burning extra fuel and required DEF (yet more input costs)

3) The emissions they are trying to reduce with the these are likely not excessively harmful from a tractor; largely because most tractors who need an SCR system is >75hp, which also means they're typically used on a large farm (100+ acres). Which dissipates the risks substantially.

For reference my 2022 Kubota tractor repeatedly had issues with the DPF / SCR system, mostly the software to enforce environmental rules. This lost us ~$20k one year due to the tractor being knocked out for a week (I was mid-cut for 140 acre hay, rained & rotted in the field post-cut).

For reference, I was very much ready to bypass the SCR system, but decided against it to keep the warranty. It had nothing to do about "right to repair", I figured out exactly how to bypass it.