Folks,
Timing the cycle is what they do.
An adversarial model relies upon using utmost leverage.
All the points made are examples.
They generally open (if the contract expiry facilitates) on an business cycle upswing, then extend into the top.
They then as the cycle rolls over, delay, let bad news (oil prices, airline collapse or the JFK assassination it matters little) then look for concessions
It is the same template at almost every airline.