Yeah why should a company that you don't work for upgrade you at absolutely no cost to them?
I guess if they did and in the future you hear a CX aircraft asking for a climb but your blocking them all the way to the US you would help out and climb as appreciated the upgrade on one of our flights.
Will you do that after dealing with our disgracefully rude and unhelpful staff travel in HKG, I very much doubt it.
As there is no statistical way to calculate the value of good will it will never be something that CX buys into. Crazy when it is a no cost item that would have a real effect on their bottom line.