"the highest performing graduates are asked to stay on as instructors"
this system has been used by the RAF in the past but on FW only - the 'creamies' (creamed off the top) may well be gifted pilots but have zero operational experience to bring to the party; something that often helps make exercises more relevant and interesting to the student.
A minority of those creamies also worked hard to get to front -line and are often not that keen to be stuck in a training job instead of mixing it with their peers.
All in all a cheap solution but effective?????