Continuing on that train of thought, I'd guess the "Amazon experts" basically just know the UI pretty well, but they won't help much with questions the hackernews community might have.
they might not right now, but presumably all calls will be recorded for quality assurance purposes. they'll assemble a list of all questions people have, at all levels, and can improve at all levels as well.
Apple's essentially owned 'end to end' for a while - they design the chips and hardware, the physical retail stores, and handle customer support. The amount of info they have on problems people have and how to optimize for that must be huge. Amazon getting in on direct customer interaction for support will give them a similar, yet different, potential usability goldmine for years to come.
I agree with you that Amazon will probably feed back on the data they receive from Mayday, and I would also assume that Apple considers that data when it designs products and considers improvements. I hope that this means that the customer service will continue to increase in quality, but I think we are looking years in the future.
Who do your parents and grandparents go to for help with their phones? In my family everyone comes to me, so even as a fairly technical person this Mayday feature seems great. :-)
Still, you're right that Amazon offers great customer service so I'll give them props for Mayday.