charity
Shrike, you are looking at it from the fo point of view.
From the company point they will employ a captain with the most experience possible.
As a passenger I would rather have an experinced captain up front rather than a fresh upgrade yet to prove his command ability.
I also believe the fo's want their command experience to go to better things so if the company upgrades an fo they have to train a new fo as well to replace him/her and can expect to see their fresh new captain leave in a few years while the ex-SAA captain is cheaper to train and is unlikely to leave.