LW sums it up in a single sentence.....
they can send us to any job and the boss do not ear a damn thing about us.
Until one reaches that capability....you are not a real asset to the operator. As a Chief Pilot....there is nothing as nice as having a group of folks workinmg with you that need only to be assigned a task knowing it will be done, done right, done safely, and the customer will be happy with it all.
Sadly....it takes a long while to get to that status....and at some point....you lose that status....but it should be an subjective decision based upon perormance and some artificial construct like "Days since Birth".