Seniority supports the weak, and protects the company from pilot migration.
We have it at Cathay and its a disaster. Dozens of contracts, but all less than the former, but leaving as a Captain generally means starting at the bottom somewhere else, so the company continues to slow erode benefits over time.
No seniority, free movement is the only way to better T and C.
This will result in the poor pilots feeling threatened and that is of course not at all palatable. So we are stuck with it.