The current training task greatly exceeds training capability. If further trainers and/or senior staff leave the capability reduces even further. You can add as many S/O's or DEFO's as you like but they will simply join a lengthy queue.
Therefore, you need to be well ahead of the Training requirement prior to any 'opening'.
Ryanair was and they have made hundreds of millions over the Northern Summer. Qantas and BA were not and have been beset by problems.
A significant number of senior staff are leaving shortly. There is one final opportunity to prevent them from doing so.