Emission control suit of requirements (both hardware & software) make these tractors failure more likely. Eg. from a youtube farmer in Sask, Ca., his NH tractor wiring harness failed because highly corrosive DEF was puked all over it. Wiring hardness is only needed to fine tune injection pump & the pletora of sensors because of regulations, and DEF is only needed because of regulations.

All of this decrease the useful lifetime of equipment.

And no, all of this is not required, a trucked was able to pass California regulations with an old pre-EPA-regulations diesel engine, but the tolerances are a lot tighter (ie. forget about that chinesium oil pump with a couple thousands too much shaft end play), maintenance is a lot trickier...