Why? At the time I joined many people wanted a career with a major airline that wasn't at a LCC. Cathay was a career airline where one could grow and end up on decent money with quality of life even If you had to step through the hoops to start. Times changed, many of the COS18 SO's have no intention to remain at Cathay. Some I fly with have used the pandemic to boost their non-aviation careers and will end up stepping away from CX/HK/Aviation completely. Spending years as a SO with no real future has gotten many bent out of shape as well.
Didn't want to hit a nerve. Just stating an obvious basic rule of life: never make yourself dependant on an anonymous organisation up to the point you can't leave. You should always have an opportunity to leave if needed, in aviation this comes with filling up your experience bag with usefull experience every day you go to work.
It seems CX SO's are really in a bad position, the pilot market in the world is opening up, but they have no valuable flight hours after several years of working as a pilot. That is bad. Should have flown some commuter aircraft instead.
The second para stated the exception, it seems you have overread that.