You are completely on it, CT.
This ain’t a thought-bubble.
If you can significantly control or influence pilot training (or have a monopoly on it), and maybe even run it at a profit, you not only control supply, but you get to control those who even commence pilot training, let alone finish it.
You get to interview them twice, once before training, and once again before employment, gaining a much greater understanding of their worth, and you get surveillance of them during training. With that surveillance you really get to know them - not just aptitude, but you get to cull those who complain when the tea-room runs out of milk - they’ll be your future union-leaders.
You also get to control things like gender balance.