Earlier quoted context omitted.
Agree wholeheartedly with everything you said except: > They didn't build the other pieces they needed for a 120-year business while they had the protection I would argue they did with things like AWS.
Similarly (or more importantly, even) is they've now built out a proprietary fulfillment and last mile delivery infrastructure that runs parallel to USPS/UPS/etc. Any new entrant is going to have to compete with Amazon on shipping cost/time. Yet Amazon can do it using their own distribution and sorting hubs, from which gig workers use their own cars to do the deliveries.
Those gig workers will dry up immediately the instant a better job opens up, and the delivery infrastructure Amazon thought it had will turn out to be owned by someone else. If the robots aren't ready in time, they will fall on their face.