A comment.
If the airlines think that a career path that lasts only 15 yrs is better for them then they are stupid. If you train a pilot and his working life is thirty years, then you would have to train two pilots at double the cost if their working life is fifteen.
On the other hand if you are recruiting then the younger of a group of qualified for the job pilots is your best bet (all other things being equal, which they almost never are,) because then it is going to be longer before you have to train another to take his place.
I'm sure you had all worked that out, sorry if I am just restating the obvious.