To clarify, I "assume" Cathay was the one that has cancelled my last leg as they were the only ones that I ever spoke to with regards to the new routes. It could have been some automated system either on AA or Cathay's side. I don't know.

Also, I was not aware of the ORC process and if I were, I probably would have taken the UA flight. Now I know.

I didn't mind the 3 legs and longer flight. As I mentioned in my OP, I was satisfied. The part that really bugged me was getting to LAX and finding that I didn't have that last flight.

Anyway, to wrap this up, Cathay is sending me a US$100 travel voucher triggered from my complaint on their website. I have no upcoming Asia trips and I don't plan to use them for a while so I wouldn't have a chance to use the voucher.