I honestly don't know the numbers, but if I had to guess, a large majority did not bring their trucks in after all the attention this is getting on the forums. We have to have ten threads about the A/C now, and the discussion has moved away from finding the root cause of the problem, to just convincing people to do the mod and measure vent temps out of context.
There doesn't have to be a bulletin. There has to be one diagnose and report that says "blend door does not function as designed", "blend door does not repeat position", "blend door does not seal against heater box", or "thermal contamination in air ducts under dash pad". All that needs to happen is a tech needs to find the issue, the service writer needs to order parts, and the warranty department needs to approve the repairs. A couple of those same diagnose and reports and there will be a cause for a STAR case, then a TSB, and then if necessary, a recall, if deemed a safety hazard. It all starts with the service department though. Can't pressure FCA to fix it my stomping our feet on a forum... Think about the squealing brakes TSB. It started out as two different STAR cases, purely based off of the number of repeated customer concerns from repeated trips to the dealer. Now there are two TSB's, and one of them is on it's third revision, meaning FCA is further investigating how to best solve the problem.