In established airlines such as CX / KA the only thing a high failure rate indicates is that their respective training departments are a JOKE.
If an airline training department can not manage to get most of their pilots (the majority of whom have been with the airline for more than 8-10 years) through the command upgrade course they have failed.
Aviation has never been an industry that promoted on ability or suitability and as a result it is quite obvious these airlines have ended up with people at key training positions that do not have a clue.
It is this sort of stubbornness and stupidity that costs airlines millions not carrying an extra 15 minutes gas.