That was actually 46 years ago. Magnuson-Moss Warranty ActYou pay hard earned dollars for equipment, IMHO, you have every right to service it yourself, and "propietary software license" has nothing to do with anything other than being an unethical profit scheme.
This scam is really no different than the manufacturer branded oil / warranty voiding controversy of 25+ years ago. The courts ruled that a manufacturer cannot void your warranty for using a different brand of oil.
I bought a compact tractor in 2019. While I would have liked 35 to 40hp, I purposely picked a model with 25hp, with the bare minimum emissions controls and electronics, to avoid being at the mercy of dealers. I just work a bit slower on bigger jobs to make up for the lack of hp. But it's silly for consumers to have to even consider such things in their purchase decisions.
I am definitely against it. i Just wish the auto makers would stop making Jelly Bean cars,,,,,,,,,,, the gazillion cars they make that no matter what brand they are, they all look the same. Just a different color, like a big bag of jelly beans