Exactly right Scoop. Only the company knows (and believe me, they know) how many pilots will be required to go through training in the future.
They know how many guys turn 65, when, and what equipment they are on, they know how many they are going to hire, they control the A/E's and they have figured out how many pilots they can push through training per month, per fleet.
Remember, new Captains or just anyone moving from one fleet to another need IOE too. That's a huge amount of training.