That's the same argument I had about the cars, but the tools got cheap and made it easier to fix the complex systems on today's cars. I think Link buss system on the diesels will drop also. I found a clean your own CAT system also.
I got lazy on my tractor, I should have immediately cleaned the water separator and change the fuel filter, had it happen on my F350 and fixed its rough run.
In reality what occurred was industry wide standardization of the diagnostics (aka: OBD port) and that allowed companies to make and sell scan tools to diagnose issues. I have a fancy Snap-On one and a cheaper Autel and both will not only give you the fault code but they will pinpoint the failed component and the Snap-On will even connect to the net and suggest replacement components. Both have saved me a bundle. My wife has a loaded Suburban and it's all electronic and I'd be lost without the diagnostic tools. having said that however, all the tractor manufacturers, from Kioti to John Deere have no standardization of diagnostic ports and no way of downloading or even reading trouble codes without a dealer only scan tool and that in my humble opinion is total BS.
Like automotive, the scan ports for the ECM/ECU's should be standard across the board, not everyone using their own protocols. All that does is marry you to a dealer for the useful life of the unit because other than changing the fluids and greasing it and filters, you cannot repair anything. without paying a dealer at X dollars an hour to read your trouble codes.
Finally, even though every make is different, they all share the same basic emissions components, made by 3rd tier suppliers like Bosch for instance.
I'll stick with my pre 4 engines because of that. With proper care and feeding I expect them to outlast me. My one Kubota has 6000 meter hours on it and I just had it in the shop for a tune up and the injectors tested. Came back with an A+ health report. My Kubota tech told me at 6K, she's just 'broken in'. I'm good with that. At 70, I'm broken in as well. I was standing there when he pulled the valve cover off. Was as clean inside as new. Not a speck of sludge, no varnish and no blowby. Inside top of the valve cover was clean as a whistle. I change the oil every spring and use the same oil every time, Shell Rotella T6. Gearboxes get Chevron All weather THC synthetic every 3 years with filters. Both units at the same time, no exceptions. Front ends get Shell Spirax 80-90 GL5 gear oil.
Never had issue one with either and I farm with both of them so they get worked. Both have loaders, both have 2 speed PTO's. One has a cab, other is open station. One is a 2002, other is a 2004.