My thoughts - completely based on personal anecdotal evidence....

Humans like and need choices, rewards, challenges, and advancements. Careers in the military and corporate worlds offer these carrots. Dead end jobs where we do the same thing and just accrue time in place are unrewarding.

Since the early times in aviation (think piston engines and tail wheels), pilots were paid more to be captain than copilot,and paid more to fly the bigger plane on the longer runs. And as pilots progressed, through life, they looked forward to moving up in equipment and seat.

I've known many - many - a pilot who agonized over whether to move up one jet (727 to DC 10, DC 10 to 747, etc) to get the rating, to fly new routes, and... to bump the pay - while accepting a lower relative bidding seniority. And, even though it's all based on simple seniority, pilots still illogically congratulate their buds on getting a captain bid, or a wide body bid.

Pay to seniority would make us all LaVerne & Shirley, putting caps on the beer bottles as they whizzed by on the conveyor belt. ( sorry millennials; Before your parents time)

The guys who want pay to seniority, I would bet, are fairly senior and want to do Florida turns in guppy but get paid the top rate. And I don't blame them. I'm doing this myself now. And if the carrot doesn't get bigger to haul my but to Germany or Japan four times a month, I'll never go back to that. Just not worth it.

Humans love to be valued. Jeffy didn't get this; we somehow believe Oscar does. But we don't get the thrill by being valued for just being here 29 years. We get the thrill from being valued as a captain, or by being valued as a wide body pilot flying to other continents.

Take away that rational, economically logical, valuation system, and pilots are zombies - paid more just to age, in place.

Just my thoughts....