If you need to be somewhere for business you simply have to pay the fare, since airlines know this they will always look to get their pound of flesh. Late last year a client wanted me at a meeting and so paid $8000 USD for an ORD-LHR return and that was only flying AA (UA was the same price, BA was an astonishing 13k)

If you want to do HKG - LAX for cheaper on CX have a look at the circle pacific fares, these are cheaper than the 8k you've been quoted with the only downside being you'll have to return via the north pacific