I remember when Mercedes cut Chrysler loose back in 2007. The service of class B vans built on Dodge Sprinters suffered as a result. I can remember some Roadtrek owners couldn't get service for their Dodge Sprinter vans at Chrysler dealerships any more. It was as if Chrysler disowned them, some refused to work on them any more, and Roadtrek bore the brunt of the problems getting basic chassis warranty work done, if I recall correctly. They had to contact specific dealerships and argue with service departments to get their van conversions serviced. It was a real mess. I guess when the warranties ran out it was every man for himself.
$h1t happens, I guess? There don't seem to be any perfect automotive service solutions. Some seem better than others, but it's all very subjective, right down to the differences between one dealership and another from the same company.