I'm not sure they will steal much traffic from CX. Most business class users are after their gold/silver (or higher) tier status of frequent flyer with both CX and oneworld. Flying HKA doesn't do them any good. Don't under estimate the power of frequent flyer points especially from somewhere like HKG thats full of very businessy types.
Granted, people who aren't tied in to these programmes will be happy to jump ship but is that alone enough to sustain the business?