If you think about it it makes perfect sense. It takes less time to train a guy who has never flown a 330 or 340 or 777 in his life but held a command in some dodgy outfit on a medium where nobody knows !!!! about the general level of standards. Than it does to move a guy Right to Left who has worked for you for three years min, knows the aircraft like the back of his hand and the routes and the laborious SOP's and has a ludicrously over the top amount of hours.
The only factor not taken into account is that as they hire the DEC's the experienced FO's leave and training doubles anyway.
On the subject of resignations did you hear one of our captains resigned by attaching his resignation to the Fatigue related ASR and sending it to the CEO. Not rumour that one, FACT and he doesent have a job to go to.