I wasn't there so I can't argue with your experience, but the fact that engineering is so heavily involved seems like the crux of the issue. These are fundamentally product and data management issues. Why would an engineer need to be involved in updating a phone number? Sure, in some cases a support issue may call into question fundamental architecture issues and require engineering to get involved. But a good product management process can look at the volume of support requests and say "90% of these could be solved with features X,Y,Z and training a support team."