Considering the current state of the service offered by CX in Y, there is not so much difference with LCCs. And if CX is so sure that their business model, they should not be afraid of LCCs in the first place.

Now the question of the slots at HKG is also a false problem. The real problem is that Air Traffic control is incapable of fully utilizing the runways. Many airports in the world can handle far more flights on 2 runways than here. So first improve the runway utilization to free more slots, but may be CX does not want this to happen after all! If you limit the slots available, you also limit the competition