I don't think there is any issue with Cathay, or any airline that is/was hesitant/slow in returning to ADL. The fact that Cathay has added more PER flights and announced a resumption of CNS in the past week is more of a reflection on Adelaide as a city rather than the airline, because if the pilot issues were really serious then CX wouldn't have added more PER flights and relaunched CNS.
Why did it take Emirates half a decade to resume flights to ADL?
Why was our national carrier unsuccessful in operating international flights out of ADL, and hence stopped?
Why is Batik exiting ADL?
It all boils down to Adelaide's role in the national and global economy, and arguably there have been some long-term shifts since the pandemic. What is the significance of Adelaide from a population, corporate and tourism perspective on the national stage, let alone the global stage? Sure you could argue the Wine Region, Kangaroo Island etc but they're easily dwarfed by places like FNQ on the global stage.
I'm not saying CX will never return, but there are reasons why it's a low priority city for many airlines.
Speaking of FNQ, CNS contrasts ADL as an example of a success story post-Covid in terms of international flight growth. CX return, SQ widebodies, VA to HND etc. QF were also planning CNS-TYO in a JV with JL but were stopped by the ACCC. Would be nice to see flights to GUM (UA 73M) and LAX (JQ 787) launched from CNS soon.