Twenty years ago at KA, pilots were upgrading between 10 months and 18 months and ageism didn't factor. Failure rates could be anywhere between 50% to 100% in certain periods. KA has a higher number of sectors than CX ( which helps ) and for all its operational peculiarities, KA was a little more practical ( having briefly had both CX SOPs and a loaned CX chief pilot as reference )
In comparison to HKA, I guess sectors were the same? What isn't factored is that these very fast upgrades were done at a time when Airbus had not documented a lot of operational procedures- especially abnormals. KA's upgrade process was draconian in its structure and complaints of a lack of training was in some part to do with Airbus not documenting explanations of handling characteristics and detailing complex failures. This was the basis of a one chance final sim assessment on a LOFT and handling exercises.
As the years roll on, command processes have to be simpler and more successful. Airlines need to adapt with the times and their competition - KA was very slow to adapt and adjust their upgrade process due well-ingrained attitudes.
Some of the now edited comments above, regarding command upgrades at HKA versus CX, lack historical context.