I've been 100 pilots from the most junior captain for almost a year now. Even 100 pilots will make a major difference when someone is trying to hold a senior domicile or upgrade to captain.

Five guys from my new hire class are in the same domicile as me and out bid me for trips. Even within my own new hire class the class seniority has made a difference. I think people really underestimate the long term effects of waiting a few months just because they feel entitled to start on a bigger plane.