NAS unlike FR doesn't have the training capacity to support the level of resignations and expansion at the same time.
I wonder. If you do some maths and calculate the number of sim hours required for TQ courses, upgrades, OPC/LPC's, RST's etc. does RYR have enough sim space for their program? That is now. What about the increase necessary as the fleet expands? It is a proven ratio. Then there is the ratio of SFI/TRI/LTC/TRE's per a/c. That is also a proven historical ratio. Have they and will they have enough? You can't be in the sim and the cockpit at the same time. The need for safety F/O's during LT is another parameter in the mix. I suspect sim time might be a limiting one.
Regarding the number leaving: an annual loss of 10% is quite common. This is made up of medical, retirement, quitting. I suspect in large stable airlines retirement is the largest part. It is predictable and manageable. It's not a surprise. I suspect the leavers are the majority at RYR and this is a surprise and unpredictable. The flexibility of the contractor scheme allows you to be over crewed at no cost. However, the resultant loss of expected earnings increases the rush to leave for those F/O's who have large debts and lower income. You can't have it both ways. It is a vicious circle towards a downward spiral that will bite you in the backside.