Manufacturers try really hard to stop their proprietary software from getting out into the world, because when it does this is exactly what happens.
Case in point: I have a $35 phone app that lets me change software configurations on my BMW, and it is great. Can't change anything related to engine, aftertreatment, or safety though...which is a good thing.
100% - I started writing a second paragraph about John Deere's fuckery, but deleted it. You are spot on.