Management look at numbers and a lack of pilot turnover has led them to believe that they are paying too much. They would like to see a certain amount of churn to know that they have got the package at the correct level. Not so high that no one ever leaves and not so low that experience levels become a problem or that the training department gets overwhelmed with new joiners.
Ryanair finally listened and improved pay and conditions only after the numbers of crew leaving resulted in flight cancellations.
Back in 1989 the Australian domestic pilots had a stranglehold on an essential service and still lost. A vast country with little alternative to air transport given the distances involved and lack of a high speed rail network. Every sector from business to tourism felt the pain and had no alternative airlines they could use.
Hong Kong obviously has no internal flights, connecting traffic can easily switch to EK, SQ, QR, EY etc. Passengers either originating in Hong Kong or having it as their destination can switch to the other airline on the route who may be able to lay on an extra flight or two. Buses could be laid on to ZGGG and ZGSZ and ferries to VMMC to catch flights from these airports.
Public sympathy would be zero if CNY travel plans were disrupted.
Disruption and inconvenience would be considerable but the starting position is much weaker than the Aussies were in 28 years ago.