I got stung with this myself and learnt my lesson the hard way.

Different situation but I had a CX award flight booked with AA miles, they took the miles out of my account and it showed as ticketed when I brought up the reservation - went to check in at HKG and they told me there was no ticket issued.

Rung AA, turns out they tried to charge my Australian credit card through the US system by accident, had some dramas - which it appears they decided not to contact me about. However they very kindly got me on a later flight that day.

The point of that story is that it's possible the OP never got the ticketing email confirming the upgrade. Obviously from my experience AA can make changes that look fine on the surface but aren't actually sorted at the other end of the spectrum. I'll know in future if I don't get a ticketing email that I need to contact AA prior to flying.

But I'm not sure what the OP was trying to achieve. Obviously it feels better to rant sometimes but my personal opinion is that someone who has seemingly flown that many miles on AA should have had a better understanding of their systems and the pitfalls that come along with it. I can feign innocence as most of my AA miles come from QF flights but I still didn't feel the need to rant about my ticketing issue, especially on an award flight where I'm not providing any revenue to the airline.