I got to thinking about what would happen at a regional if they eliminated seniority (specifically for upgrades). They could hire street captains at first year pay and keep all the senior first officers on f/o pay. Sounds crazy, but it's what I would do if I didn't have to upgrade based on seniority. Not only that, I've seen something similar: New hires recruited to a high paid position while current employees are allowed to stay, albeit in a lower paid position.