My wife’s cousin is a dealer mechanic, and he described this really perverse incentive WRT GM. If the dealership sees a particular failure mode and reports it

My wife’s cousin is a dealer mechanic, and he described this really perverse incentive WRT GM. If the dealership sees a particular failure mode and reports it to GM, then they’ll issue a TSB (or maybe even trigger a recall). But in doing so, they’ll only pay a fixed fee to the dealer. Instead, what happens is that the dealer has an incentive to build a local knowledge base on how to fix the common problems but not share it with GM as they can bill the repairs hourly. (The specific failure mode he used as an example was inadequate weatherproofing in door electrics. The local fix was to pop-rivet the bottom of a plastic container in the right place so as to improve weather resistance)