This means a talented junior gets screwed and leaves, and the one year twenty times over crowd stay forever.
I went through a pay review where I was apparently too far up the curve for my age and that wasn't fair, so I got less than my colleagues that round. That's a conversation you only get to have with an engineer once.
A program (representing a strategic goal) can contain multiple projects big and small. Perhaps the author wants to convey programs which map to company or divisions strategic initiatives.
https://en.m.wikipedia.org/wiki/Milestone
I think the term is rather unimportant. You could also use the term epic.
Still it missed “how should I fire new junior engineers”