Seniority is a HR managers wet dream
There may have being good reasons for it in the legacy world of regulated airlines with limited opportunities to move but right now seniority is win win for companies.
One reason is it makes the very vexing scheduling issue easier to deal with.
The big bonus is it keep the pilots as effectively indentured servants. No other industry does this, not one. The one thing that all managers fear is employees, particularly employees with expensive training, heading for the door. Only airline pilots face starting over at the bottom as a penalty for leaving so they logically will sit there enduring death by a thousand cuts.
Spare me about the unscrupulous operators, etc. They will always be there.
Don't go on about how I did , so you can suffer through - that is the problem.
It would be simple enough to have a system thats rotates bidding rights fairly among all pilots and pays for seniority based on time in the company and not on equipment or routes. If your pay and work conditions are not going to be impacted what you fly and what you get paid why would you care where the newbie comes in at ?
Command upgrades could be an issue but that can be worked out.
If pilots were smart they would work a system where they were truly freelancers working for the highest bidder. The insurance companies will control the bottom end as they will force companies to have standards. (That is assuming there is a correlation between cockpit competence and loss rate, there is right?)